Fix tls_get_addr handling for glibc >=2.25

This changes the sanitizers' tls_get_addr handling from
a heuristic check of __signal_safe_memalign allocations
(which has only been used in a since deprecated version
of Google's runtime), to using the sanitizers' interface
function to check if it is a malloc allocation (used
since glibc >= 2.25).

This is one of the approaches proposed by Keno in
https://github.com/google/sanitizers/issues/1409#issuecomment-1214244142

This moves the weak annotation of __sanitizer_get_allocated_size/begin from the header to sanitizer_tls_get_addr.cpp, as suggested by Vitaly in D148060.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D147459