[AArch64] Use fmin/fmax for v[min|max]nm{q} intrinsics

[AArch64] Use fmin/fmax for v[min|max]nm{q} intrinsics

  smin/smax will actually honor quiet NaN.

gcc/
	* config/aarch64/aarch64-simd-builtins.def (smax): Remove float
	variants.
	(smin): Likewise.
	(fmax): New entry.
	(fmin): Likewise.
	* config/aarch64/arm_neon.h (vmaxnm_f32): Use
	__builtin_aarch64_fmaxv2sf.
	(vmaxnmq_f32): Likewise.
	(vmaxnmq_f64): Likewise.
	(vminnm_f32): Likewise.
	(vminnmq_f32): Likewise.
	(vminnmq_f64): Likewise.

gcc/testsuite/

	* gcc.target/aarch64/simd/vminmaxnm_1.c: New.

From-SVN: r238166