[CSSPGO][Test] XFAIL profile-context-tracker-debug.ll on AIX

The case start to fail since https://reviews.llvm.org/D99351.

Looks like to me that the node order within Context Profile Tree depends
on the implmementation of std::hash<std::string>.

Unfortunately, the current clang implementation generate different values on
AIX (or for all big-endian systems?)

On Linux:
main: 2408804140(0x8f936f2c)
external:  896680882(0x357243b2)
externalA:  620231129(0x24f7f9d9)

On AIX:
main:  994322777(0x3b442959)
external: 3548191215(0xd37d19ef)
externalA: 1390365101(0x52df49ad)

XFAIL it first while we discuss and seek for a fix.

Reviewed By: wenlei

Differential Revision: https://reviews.llvm.org/D99815