[turbofan] Implemented the optional Float32RoundTiesEven operator.

src/compiler/arm/code-generator-arm.cc

Index: src/compiler/arm/code-generator-arm.cc
diff --git a/src/compiler/arm/code-generator-arm.cc b/src/compiler/arm/code-generator-arm.cc
index e5152812c9721da9b630ab1c8fb59affebefb87b..2ba1a8a3790b1a7ff477895caa25424201654cf9 100644
--- a/src/compiler/arm/code-generator-arm.cc
+++ b/src/compiler/arm/code-generator-arm.cc
@@ -812,6 +812,9 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kArmVrintaF64:
       __ vrinta(i.OutputFloat64Register(), i.InputFloat64Register(0));
       break;
+    case kArmVrintnF32:
+      __ vrintn(i.OutputFloat32Register(), i.InputFloat32Register(0));
+      break;
     case kArmVrintnF64:
       __ vrintn(i.OutputFloat64Register(), i.InputFloat64Register(0));
       break;