llvmpasses: force vector width for compatibility with non-x86 hosts. (JuliaLang#56300)

The pipeline-prints test currently fails when running on an
aarch64-macos device:

```
/Users/tim/Julia/src/julia/test/llvmpasses/pipeline-prints.ll:309:23: error: AFTERVECTORIZATION: expected string not found in input
; AFTERVECTORIZATION: vector.body
                      ^
<stdin>:2:40: note: scanning from here
; *** IR Dump Before AfterVectorizationMarkerPass on julia_f_199 ***
                                       ^
<stdin>:47:27: note: possible intended match here
; *** IR Dump Before AfterVectorizationMarkerPass on jfptr_f_200 ***
                          ^

Input file: <stdin>
Check file: /Users/tim/Julia/src/julia/test/llvmpasses/pipeline-prints.ll

-dump-input=help explains the following input dump.

Input was:
<<<<<<
             1: opt: WARNING: failed to create target machine for 'x86_64-unknown-linux-gnu': unable to get target for 'x86_64-unknown-linux-gnu', see --version and --triple.
             2: ; *** IR Dump Before AfterVectorizationMarkerPass on julia_f_199 ***
check:309'0                                            X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
             3: define i64 @julia_f_199(ptr addrspace(10) noundef nonnull align 16 dereferenceable(40) %0) #0 !dbg !4 {
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
             4: top:
check:309'0     ~~~~~
             5:  %1 = call ptr @julia.get_pgcstack()
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
             6:  %ptls_field = getelementptr inbounds ptr, ptr %1, i64 2
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
             7:  %ptls_load45 = load ptr, ptr %ptls_field, align 8, !tbaa !8
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
             .
             .
             .
            42:
check:309'0     ~
            43: L41: ; preds = %L41.loopexit, %L17, %top
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            44:  %value_phi10 = phi i64 [ 0, %top ], [ %7, %L17 ], [ %.lcssa, %L41.loopexit ]
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            45:  ret i64 %value_phi10, !dbg !52
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            46: }
check:309'0     ~~
            47: ; *** IR Dump Before AfterVectorizationMarkerPass on jfptr_f_200 ***
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:309'1                               ?                                           possible intended match
            48: ; Function Attrs: noinline optnone
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            49: define nonnull ptr addrspace(10) @jfptr_f_200(ptr addrspace(10) %0, ptr noalias nocapture noundef readonly %1, i32 %2) #1 {
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            50: top:
check:309'0     ~~~~~
            51:  %3 = call ptr @julia.get_pgcstack()
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            52:  %4 = getelementptr inbounds ptr addrspace(10), ptr %1, i32 0
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
             .
             .
             .
>>>>>>

--

********************
Failed Tests (1):
  Julia :: pipeline-prints.ll
```

The problem is that these tests assume x86_64, which fails because the
target isn't available, so it presumably uses the native target which
has different vectorization characteristics:

```
❯ ./usr/tools/opt --load-pass-plugin=libjulia-codegen.dylib -passes='julia' --print-before=AfterVectorization -o /dev/null ../../test/llvmpasses/pipeline-prints.ll
./usr/tools/opt: WARNING: failed to create target machine for 'x86_64-unknown-linux-gnu': unable to get target for 'x86_64-unknown-linux-gnu', see --version and --triple.
```

There's other tests that assume this (e.g. the `fma` cpufeatures one),
but they don't fail, so I've left them as is.

Author: maleadt

test/llvmpasses/pipeline-prints.ll

@@ -14,7 +14,7 @@
 ; RUN: opt --load-pass-plugin=libjulia-codegen%shlibext -passes='julia' --print-before=BeforeScalarOptimization -o /dev/null %s 2>&1 | FileCheck %s --check-prefixes=BEFORESCALAROPTIMIZATION
 ; RUN: opt --load-pass-plugin=libjulia-codegen%shlibext -passes='julia' --print-before=AfterScalarOptimization -o /dev/null %s 2>&1 | FileCheck %s --check-prefixes=AFTERSCALAROPTIMIZATION
 ; RUN: opt --load-pass-plugin=libjulia-codegen%shlibext -passes='julia' --print-before=BeforeVectorization -o /dev/null %s 2>&1 | FileCheck %s --check-prefixes=BEFOREVECTORIZATION
-; RUN: opt --load-pass-plugin=libjulia-codegen%shlibext -passes='julia' --print-before=AfterVectorization -o /dev/null %s 2>&1 | FileCheck %s --check-prefixes=AFTERVECTORIZATION
+; RUN: opt --load-pass-plugin=libjulia-codegen%shlibext -passes='julia' --print-before=AfterVectorization -force-vector-width=2 -o /dev/null %s 2>&1 | FileCheck %s --check-prefixes=AFTERVECTORIZATION
 ; RUN: opt --load-pass-plugin=libjulia-codegen%shlibext -passes='julia' --print-before=BeforeIntrinsicLowering -o /dev/null %s 2>&1 | FileCheck %s --check-prefixes=BEFOREINTRINSICLOWERING
 ; RUN: opt --load-pass-plugin=libjulia-codegen%shlibext -passes='julia' --print-before=AfterIntrinsicLowering -o /dev/null %s 2>&1 | FileCheck %s --check-prefixes=AFTERINTRINSICLOWERING
 ; RUN: opt --load-pass-plugin=libjulia-codegen%shlibext -passes='julia' --print-before=BeforeCleanup -o /dev/null %s 2>&1 | FileCheck %s --check-prefixes=BEFORECLEANUP
@@ -311,4 +311,4 @@ attributes #2 = { inaccessiblemem_or_argmemonly }
 
 ; COM: Intrinsics are lowered and cleaned up by the time optimization is finished
 ; AFTEROPTIMIZATION-NOT: call void @julia.safepoint
-; AFTEROPTIMIZATION: load volatile i64{{.*}}%safepoint
+; AFTEROPTIMIZATION: load volatile i64{{.*}}%safepoint