Add notinbranch/inbranch flags to attribute __simd__.

Add notinbranch/inbranch flags to attribute __simd__.

gcc/
	* c-family/c-common.c (c_common_attribute_table[]): Update max arguments
	count for "simd" attribute.
	(handle_simd_attribute): Parse "notinbranch" and "inbranch" arguments.
	* doc/extend.texi ("simd"): Describe new flags.
gcc/testsuite/
	* c-c++-common/attr-simd-4.c: New test.
	* c-c++-common/attr-simd-5.c: New test.

From-SVN: r231270