This change eliminates the Android-specific --android-memtag-* flags
from lld, replacing them with -z memtag-* generic equivalents. With
these generic flags, the linker will emit only the dynamic array tags
specified in the "Memtag ABI Extension to ELF", but no Android-specific
memtag note.
In addition, this change adds an --android-memtag-note flag which should
be used when the Android-specific memtag note should be emitted.
This change also modifies the clang driver to make use of the new flags.
ebd62d652c