Fix zen6 AVX512BMM cpuid check.

- Moved bit_AVX512BMM to extended features section.
- Added test for __builtin_cpu_supports ("avx512bmm") compile and runtime tests.

gcc/ChangeLog:

	* common/config/i386/cpuinfo.h (get_available_features): Detect AVX512BMM from
	extended features instead of standard leaf.
	* config/i386/cpuid.h (bit_AVX512BMM): Move to extended features
	section.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/avx512bmm-check-1.c: New test.
	* gcc.target/i386/avx512bmm-check-2.c: New test.
	* gcc.target/i386/avx512bmm-check-3.c: New test.

(cherry picked from commit 33053605189f2b903b1a0d730a1feec166e89735)