[AIX] Disable tests that fail because of no 64-bit XCOFF object file support

The modified tests fail because 64-bit XCOFF object files are not currently supported on AIX. This patch disables these tests on 64-bit AIX for now.

This patch is similar to D111887 except the failures on this patch are on a 64-bit build.

Reviewed By: shchenz, #powerpc

Differential Revision: https://reviews.llvm.org/D113049