gcc-4.9: move binaries to find build breakages

As per:
https://android.googlesource.com/platform/prebuilts/clang/host/linux-x86/+/master/GCC_4_9_DEPRECATION.md
We're about to remove gcc-4.9; move the binaries to see if we can spot
any build breakages in pre or post submit testing.

Build cops may revert this change if necessary.

Please report any unexpected build breakages to: android-llvm@googlegroups.com

Bug: 147240075
Change-Id: I05a4956ea149b4eb0b62d2f09798605ad9e6aeda
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
8 files changed