Don't dead-end asan_foo() entrypoints in the shim

Some entrypoints supporting LLDB process introspection were not
being forwarded to asan_abi_foo() stable ABI entrypoints which
effectively dead-ended them in NOPs that could not be implemented
by Stable ABI.

rdar://115974403

Reviewed By: wrotki, vitalybuka, MaskRay

Differential Revision: https://reviews.llvm.org/D159545