This commit resolves the compression performance regression in
real-time encoding setting when high bit-depth mode is enabled.

The current solution temporarily disables the SIMD implementations
of vpx_satd, hadamard8x8, and hadamard16x16 in high bit-depth mode.

The commit makes the coding results bit-wise identical between
regular coding pipeline and high bit-depth at profile 0.

BUG=webm:1365

Change-Id: Icfb900821733749685370460a1a5a7e07f76f4bf