[Clang][OpenMP]Solved the the always truth condition in Arm64

There was a bug in the getAArch64MTV function on the third if statement which returns truth  as reported by this issue [[ https://github.com/llvm/llvm-project/issues/61319 |[Clang] Condition is always true which is caused by a possible copy-pasted bug in CGOpenMPRuntime.cpp
 ]].
All the testcases are passing. The first unit tests I could find are for functions that are 6 levels from this issue. The function is very low level and couldn't find a way to affect it from the higher functions.

Reviewed By: jhuber6

Differential Revision: https://reviews.llvm.org/D146370