Revert "Revert "gcc-4.9: move binaries to find build breakages""

This reverts commit 4416b2071855d71b6ee06d71540acac1a1d66672.

This re-renames the gcc binary to cause explicit breakage.  It may be reverted by buildcop.

Reason for revert: unless the mingw builds also required this, I don't think this was the source of any of the reported failures.
Bug: 147240075
Change-Id: Ib82436bd003150c6a54041ac61399fcbbceb6eeb
11 files changed