[llvm] [SLP] Move some of X86 tests to common directory (PR #106401)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `openmp-offload-sles-build-only` running on `rocm-worker-hw-04-sles` while building `llvm` at step 8 "Add check check-llvm".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/140/builds/5347

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 8 (Add check check-llvm) failure: test (failure)
******************** TEST 'LLVM :: Transforms/SLPVectorizer/alternate-cmp-swapped-pred-parent.ll' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 3: /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/opt < /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/Transforms/SLPVectorizer/alternate-cmp-swapped-pred-parent.ll -mtriple=x86_64-unknown -passes=slp-vectorizer -S -slp-threshold=-1000 | /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/FileCheck /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/Transforms/SLPVectorizer/alternate-cmp-swapped-pred-parent.ll
+ /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/opt -mtriple=x86_64-unknown -passes=slp-vectorizer -S -slp-threshold=-1000
+ /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/FileCheck /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/Transforms/SLPVectorizer/alternate-cmp-swapped-pred-parent.ll
RUN: at line 4: /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/opt < /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/Transforms/SLPVectorizer/alternate-cmp-swapped-pred-parent.ll -mtriple=aarch64-unknown-linux-gnu -passes=slp-vectorizer -S -slp-threshold=-1000 | /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/FileCheck /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/Transforms/SLPVectorizer/alternate-cmp-swapped-pred-parent.ll
+ /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/opt -mtriple=aarch64-unknown-linux-gnu -passes=slp-vectorizer -S -slp-threshold=-1000
+ /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/FileCheck /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/Transforms/SLPVectorizer/alternate-cmp-swapped-pred-parent.ll
/home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/opt: warning: failed to infer data layout: unable to get target for 'aarch64-unknown-linux-gnu', see --version and --triple.
/home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/opt: WARNING: failed to create target machine for 'aarch64-unknown-linux-gnu': unable to get target for 'aarch64-unknown-linux-gnu', see --version and --triple.
/home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/Transforms/SLPVectorizer/alternate-cmp-swapped-pred-parent.ll:13:15: error: CHECK-NEXT: expected string not found in input
; CHECK-NEXT: [[TMP0:%.*]] = insertelement <8 x i16> <i16 0, i16 0, i16 0, i16 poison, i16 poison, i16 poison, i16 0, i16 poison>, i16 [[CALL37]], i32 3
              ^
<stdin>:11:39: note: scanning from here
 %call = load i16, ptr poison, align 2
                                      ^
<stdin>:11:39: note: with "CALL37" equal to "%call37"
 %call = load i16, ptr poison, align 2
                                      ^
/home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/Transforms/SLPVectorizer/alternate-cmp-swapped-pred-parent.ll:44:15: error: CHECK-NEXT: expected string not found in input
; CHECK-NEXT: [[TMP0:%.*]] = insertelement <8 x i16> <i16 0, i16 0, i16 0, i16 poison, i16 poison, i16 poison, i16 poison, i16 0>, i16 [[CALL]], i32 3
              ^
<stdin>:31:41: note: scanning from here
 %call37 = load i16, ptr poison, align 2
                                        ^
<stdin>:31:41: note: with "CALL" equal to "%call"
 %call37 = load i16, ptr poison, align 2
                                        ^

Input file: <stdin>
Check file: /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/Transforms/SLPVectorizer/alternate-cmp-swapped-pred-parent.ll

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

Input was:
<<<<<<
           .
           .
           .
           6: entry: 
           7:  %call37 = load i16, ptr poison, align 2 
           8:  br label %bb 
           9:  
          10: bb: ; preds = %entry 
          11:  %call = load i16, ptr poison, align 2 
next:13'0                                           X error: no match found
next:13'1                                             with "CALL37" equal to "%call37"
...

```

</details>

https://github.com/llvm/llvm-project/pull/106401