[AIX][XCOFF] Use bit order of has_vec and longtbtable bits as defined in AIX header...

[AIX][XCOFF] Use bit order of has_vec and longtbtable bits as defined in AIX header debug.h

Summary:

  The bit order of the has_vec and longtbtable bits in the traceback table generated by the XL compiler flipped at some point after v12.1. This is different from the definition is the AIX header debug.h. The change in the XL compiler that caused the deviation from the OS header definition was unintentional. Since both orderings are extant and the XL compiler runtime also expects the ordering defined by the OS, we will correct the output from LLVM to match the defined ordering given by the OS (which is also consistent with the Assembler Language Reference). Mitigation for traceback tables encoded with the wrong ordering is required for either ordering.

Reviewers: XingXue, HubertTong
Differential Revision: https://reviews.llvm.org/D105487