Add -whole-archive around the ASan runtime archive in the link command.

This ensures that even though it comes first, we pick up its .o files.
Note that if we can use this (or something similar / equivalent) on
other platforms, we could potentially remove
ReplaceOperatorsNewAndDelete from the ASan runtimes.

We should probably do something similar for TSan and MSan as well.

llvm-svn: 169328