[GlobalISel][AArch64] Legalize G_FNEARBYINT

Add legalizer support for G_FNEARBYINT. It's the same as G_FCEIL etc.

Since the importer allows us to automatically select this after legalization,
also add tests for selection etc. Also update arm64-vfloatintrinsics.ll.

llvm-svn: 359204
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index c24418e..c62ad0d 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -1323,6 +1323,7 @@
   case TargetOpcode::G_FLOG:
   case TargetOpcode::G_FLOG2:
   case TargetOpcode::G_FRINT:
+  case TargetOpcode::G_FNEARBYINT:
   case TargetOpcode::G_FSQRT:
   case TargetOpcode::G_FEXP:
   case TargetOpcode::G_FEXP2:
@@ -2191,6 +2192,7 @@
   case G_FLOG:
   case G_FLOG2:
   case G_FLOG10:
+  case G_FNEARBYINT:
   case G_FCEIL:
   case G_FFLOOR:
   case G_FRINT: