tsan: add kBrokenAliasedMetas condition and test
This fills in a gap in the tsan_shadow_test coverage:
it is possible that the meta regions are aliased
(e.g., the heap meta region overlaps the high app meta
region). Indeed, the Aarch64_39 mapping has been
silently broken in this way for quite some time.
This CL checks whether the individual meta regions
(for low/mid/high/heap) overlap. Note that
(!kBrokenAliasedMetas && !kBrokenLinearity) implies
that MemToMeta is invertible; we cannot directly
test MetaToMem because that function does not exist.
Differential Revision: https://reviews.llvm.org/D141445