[clang][AIX] Remove Newly Added Target Dependent Test Case

https://reviews.llvm.org/D144190 added a test case that is target dependent and requires assembly code generation, which fails on x64 and aarch64 buildbots. This patch removes the test case. We have test cases for code generation added in https://reviews.llvm.org/D144189 already and this removed case was nice to have.

Differential Revision: https://reviews.llvm.org/D150586