MIPS: ARM: Load undefined receiver sentinel without constant pool.

Port a820568b

Each call to emit_32 uses 5 constant pool slots:
* the "emit_32" string
* undefined (the receiver)
* the argument (heap number)
* the load IC
* the call IC

This change cuts that down 20% to 4, by loading the undefined from the heap roots.

BUG=

Review URL: https://codereview.chromium.org/963193005

Cr-Commit-Position: refs/heads/master@{#26995}

src/mips/builtins-mips.cc

@@ -941,7 +941,9 @@ static void CallCompileOptimized(MacroAssembler* masm, bool concurrent) {
   // Push function as parameter to the runtime call.
   __ Push(a1, a1);
   // Whether to compile in a background thread.
-  __ Push(masm->isolate()->factory()->ToBoolean(concurrent));
+  __ LoadRoot(
+      at, concurrent ? Heap::kTrueValueRootIndex : Heap::kFalseValueRootIndex);
+  __ push(at);
 
   __ CallRuntime(Runtime::kCompileOptimized, 2);
   // Restore receiver.

src/mips/full-codegen-mips.cc

@@ -2895,7 +2895,8 @@ void FullCodeGenerator::EmitCallWithLoadIC(Call* expr) {
     }
     // Push undefined as receiver. This is patched in the method prologue if it
     // is a sloppy mode method.
-    __ Push(isolate()->factory()->undefined_value());
+    __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
+    __ push(at);
   } else {
     // Load the function from the receiver.
     DCHECK(callee->IsProperty());

src/mips64/builtins-mips64.cc

@@ -950,7 +950,9 @@ static void CallCompileOptimized(MacroAssembler* masm, bool concurrent) {
   // Push function as parameter to the runtime call.
   __ Push(a1, a1);
   // Whether to compile in a background thread.
-  __ Push(masm->isolate()->factory()->ToBoolean(concurrent));
+  __ LoadRoot(
+      at, concurrent ? Heap::kTrueValueRootIndex : Heap::kFalseValueRootIndex);
+  __ push(at);
 
   __ CallRuntime(Runtime::kCompileOptimized, 2);
   // Restore receiver.

src/mips64/full-codegen-mips64.cc

@@ -2896,7 +2896,8 @@ void FullCodeGenerator::EmitCallWithLoadIC(Call* expr) {
     }
     // Push undefined as receiver. This is patched in the method prologue if it
     // is a sloppy mode method.
-    __ Push(isolate()->factory()->undefined_value());
+    __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
+    __ push(at);
   } else {
     // Load the function from the receiver.
     DCHECK(callee->IsProperty());