make debug match release build on win32 with 8x8 transform enabled

The 8x8 forward transform makes use of floating operations, therefore
requires emms call to reset mmx registers to correct state. Without
the resets, the 8x8 forward transform results are indefinite on win32
platform.

Change-Id: Ib5b71c3213e10b8a04fe776adf885f3714e7deb1