Turn FastNewContextStub into a HydrogenCodeStub.

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 37d5cf945d69281e478681b57434a6f94a9f7d2c..47be6cdf613dd15449a93095ebe34af3abd9de50 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -207,17 +207,18 @@ bool LCodeGen::GeneratePrologue() {
   if (heap_slots > 0) {
     Comment(";;; Allocate local context");
     // Argument to NewContext is the function, which is in r1.
-    __ push(r1);
     if (heap_slots <= FastNewContextStub::kMaximumSlots) {
       FastNewContextStub stub(heap_slots);
       __ CallStub(&stub);
     } else {
+      __ push(r1);
       __ CallRuntime(Runtime::kNewFunctionContext, 1);
     }
     RecordSafepoint(Safepoint::kNoLazyDeopt);
     // Context is returned in both r0 and cp.  It replaces the context
     // passed to us.  It's saved in the stack and kept live in cp.
-    __ str(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
+    __ mov(cp, r0);
+    __ str(r0, MemOperand(fp, StandardFrameConstants::kContextOffset));
     // Copy any necessary parameters into the context.
     int num_parameters = scope()->num_parameters();
     for (int i = 0; i < num_parameters; i++) {