[llvm] [X86] Add TuningSlowPDEP/PEXT flags and control vector PDEP/PEXT scalarization with them (PR #218980)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ml-opt-devrel-x86-64` running on `ml-opt-devrel-x86-64-b2` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/175/builds/1909

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/X86/znver-pdep.ll' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/b/ml-opt-devrel-x86-64-b1/build/bin/llc < /b/ml-opt-devrel-x86-64-b1/llvm-project/llvm/test/CodeGen/X86/znver-pdep.ll -mtriple=x86_64-- -mcpu=znver1 | /b/ml-opt-devrel-x86-64-b1/build/bin/FileCheck /b/ml-opt-devrel-x86-64-b1/llvm-project/llvm/test/CodeGen/X86/znver-pdep.ll --check-prefixes=CHECK,SLOW-ZNVER
# executed command: /b/ml-opt-devrel-x86-64-b1/build/bin/llc -mtriple=x86_64-- -mcpu=znver1
# executed command: /b/ml-opt-devrel-x86-64-b1/build/bin/FileCheck /b/ml-opt-devrel-x86-64-b1/llvm-project/llvm/test/CodeGen/X86/znver-pdep.ll --check-prefixes=CHECK,SLOW-ZNVER
# .---command stderr------------
# | /b/ml-opt-devrel-x86-64-b1/llvm-project/llvm/test/CodeGen/X86/znver-pdep.ll:1013:15: error: CHECK-NEXT: is not on the line after the previous match
# | ; CHECK-NEXT: pdepl %eax, %ecx, %eax
# |               ^
# | <stdin>:495:2: note: 'next' match was here
# |  pdepl %eax, %ecx, %eax
# |  ^
# | <stdin>:493:19: note: previous match ended here
# |  vmovd %xmm0, %edx
# |                   ^
# | <stdin>:494:1: note: non-matching line after previous match is here
# |  vpextrd $2, %xmm0, %esi
# | ^
# | /b/ml-opt-devrel-x86-64-b1/llvm-project/llvm/test/CodeGen/X86/znver-pdep.ll:1036:15: error: CHECK-NEXT: is not on the line after the previous match
# | ; CHECK-NEXT: vpextrd $1, %xmm2, %eax
# |               ^
# | <stdin>:519:2: note: 'next' match was here
# |  vpextrd $1, %xmm2, %eax
# |  ^
# | <stdin>:516:31: note: previous match ended here
# |  vextracti128 $1, %ymm1, %xmm2
# |                               ^
# | <stdin>:517:1: note: non-matching line after previous match is here
# |  vpextrd $1, %xmm0, %r8d
# | ^
# | /b/ml-opt-devrel-x86-64-b1/llvm-project/llvm/test/CodeGen/X86/znver-pdep.ll:1079:15: error: CHECK-NEXT: expected string not found in input
# | ; CHECK-NEXT: vmovq %xmm1, %rdx
# |               ^
# | <stdin>:559:25: note: scanning from here
# |  vpextrq $1, %xmm0, %rcx
# |                         ^
# | <stdin>:561:2: note: possible intended match here
# |  vmovq %xmm0, %rdx
# |  ^
# | /b/ml-opt-devrel-x86-64-b1/llvm-project/llvm/test/CodeGen/X86/znver-pdep.ll:1096:15: error: CHECK-NEXT: expected string not found in input
# | ; CHECK-NEXT: vpextrq $1, %xmm1, %rsi
# |               ^
# | <stdin>:576:31: note: scanning from here
# |  vextracti128 $1, %ymm0, %xmm3
# |                               ^
# | <stdin>:585:2: note: possible intended match here
...

```

</details>

https://github.com/llvm/llvm-project/pull/218980