Revert "Disable -Wno-single-bit-bitfield-constant-conversion locally" am: c667749398 am: 078e949147

Original change: https://android-review.googlesource.com/c/platform/external/python/cpython2/+/3249252

Change-Id: I0cdf42f8257017dce579984797594f78d71d92b9
Signed-off-by: Automerger Merge Worker <[email protected]>