[x86][AArch64] adjust fast-math-flags in tests; NFC

This goes with the proposal in D86403.

Author: rotateright

llvm/test/CodeGen/AArch64/sqrt-fastmath.ll

@@ -493,7 +493,7 @@ define <2 x double> @sqrt_fdiv_common_operand_vec(<2 x double> %x) nounwind {
 ; CHECK-NEXT:    fmul v0.2d, v0.2d, v1.2d
 ; CHECK-NEXT:    ret
   %sqrt = call <2 x double> @llvm.sqrt.v2f64(<2 x double> %x)
-  %r = fdiv arcp reassoc <2 x double> %x, %sqrt
+  %r = fdiv nsz arcp reassoc <2 x double> %x, %sqrt
   ret <2 x double> %r
 }
 

llvm/test/CodeGen/X86/sqrt-fastmath.ll

@@ -930,7 +930,7 @@ define <2 x double> @sqrt_fdiv_common_operand_vec(<2 x double> %x) nounwind {
 ; AVX-NEXT:    vdivpd %xmm1, %xmm0, %xmm0
 ; AVX-NEXT:    retq
   %sqrt = call <2 x double> @llvm.sqrt.v2f64(<2 x double> %x)
-  %r = fdiv arcp reassoc <2 x double> %x, %sqrt
+  %r = fdiv nsz arcp reassoc <2 x double> %x, %sqrt
   ret <2 x double> %r
 }