[turbofan] Properly lower NumberTan to Float64Tan.

TBR=mvstanton@chromium.org
BUG=v8:5086,v8:5126

Review-Url: https://codereview.chromium.org/2080233002
Cr-Commit-Position: refs/heads/master@{#37100}

src/compiler/representation-change.cc

@@ -698,6 +698,8 @@ const Operator* RepresentationChanger::Float64OperatorFor(
       return machine()->Float64Log10();
     case IrOpcode::kNumberSin:
       return machine()->Float64Sin();
+    case IrOpcode::kNumberTan:
+      return machine()->Float64Tan();
     case IrOpcode::kNumberSqrt:
       return machine()->Float64Sqrt();
     case IrOpcode::kNumberCbrt:

src/compiler/simplified-lowering.cc

@@ -1539,7 +1539,8 @@ class RepresentationSelector {
       case IrOpcode::kNumberLog2:
       case IrOpcode::kNumberLog10:
       case IrOpcode::kNumberCbrt:
-      case IrOpcode::kNumberSin: {
+      case IrOpcode::kNumberSin:
+      case IrOpcode::kNumberTan: {
         VisitUnop(node, UseInfo::TruncatingFloat64(),
                   MachineRepresentation::kFloat64);
         if (lower()) NodeProperties::ChangeOp(node, Float64Op(node));