Build: Fix 12-bit FP tests w/ 32-bit builds With x86-64 builds, the default value of FLOATTEST works with both the 8-bit-per-sample and 12-bit-per-sample flavors of the libjpeg API library. However, that is not the case with x86 builds. Thus, we need separate 8-bit-per-sample and 12-bit-per-sample FLOATTEST variables.