Revert "Fix the libgcc/libatomic link order."

This caused a lot of failures in the libc++ tests, since linking
libgcc.a before libc++.so means that the wrong unwinder will be used.

This patch is still correct, but I will revert for now while I find a
good way to apply it without breaking unwinding.

This reverts commit 741b36e9.

Change-Id: I57e0b89534adf5c1677dbf2f64ac750e74bd5fbf