Adds the functions proc_num_simd_sse_avx_registers() and proc_num_simd_sse_avx_saved() that replace proc_num_simd_registers() and proc_num_simd_saved() internally when they are used to access fixed size structures like sigcontext, fpstate or xstate, i.e. the structure sizes don't contiguously extend to AVX-512. The new functions need to be used in favor of the existing ones, e.g. to access xmm and ymmh data of formerly mentioned structures.
Adds the define MCXT_NUM_SIMD_SSE_AVX_SLOTS used in the same manner as described above.
This patch prepares DynamoRIO to switch the exported proc_num_simd_registers() to AVX-512 extended number of registers if there is feature support of the processor and OS.
Issue: #1312