[asan][darwin] This test is x86_64 specific, not non-ios in general.

This test was unsupported in iOS when a more accurate test is that the architecture is x86_64. This "fix" is first in a series of updates intended to get asan arm64 tests fully functional.

Reviewed By: thetruestblue, vitalybuka

Differential Revision: https://reviews.llvm.org/D138001