Use LLD for partialLd.

Clang will soon start using relocations that are currently unsupported by
the version of ld.bfd that Android uses when HWASAN is enabled. This will
cause partialLd to fail since the clang driver defaults to ld.bfd.

Switch to using LLD, since it will support those relocations.

Change-Id: I0964f53dc63773f3b52bb377f863df9c39961a07