Merge 94100bc2fb1a39dbeb43d18a95176097c53f1324 into 18.x

[brad0]

[OpenMP][AIX]Add assembly file containing microtasking
routines and unnamed common block definitions (#81770)

This patch adds assembly file z_AIX_asm.S that contains the 32- and
64-bit XCOFF version of microtasking routines and unnamed common block
definitions. This code has been run through the libomp LIT tests and a
user package successfully.

[brad0]

/cherry-pick 94100bc

[llvmbot]

@llvm/issue-subscribers-openmp

Author: Brad Smith (brad0)

[OpenMP][AIX]Add assembly file containing microtasking routines and unnamed common block definitions (#81770)

This patch adds assembly file z_AIX_asm.S that contains the 32- and
64-bit XCOFF version of microtasking routines and unnamed common block
definitions. This code has been run through the libomp LIT tests and a
user package successfully.

[llvmbot]

/pull-request #82391