PPC: [Interpreter] Save bytecode offset in interpreter stack frames.

Port 025d476c

Original commit message:
    Adds a slot for the bytecode offset to interpreter stack frames and
    saves it on calls, and restores after calls.

    Also fixes RawMachineAssembler::Return() to call MergeControlToEnd.

R=rmcilroy@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1531873002

Cr-Commit-Position: refs/heads/master@{#32920}

src/ppc/builtins-ppc.cc

@@ -763,6 +763,10 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   __ addi(fp, sp, Operand(StandardFrameConstants::kFixedFrameSizeFromFp));
   __ push(r6);
 
+  // Push zero for bytecode array offset.
+  __ li(r3, Operand::Zero());
+  __ push(r3);
+
   // Get the bytecode array from the function object and load the pointer to the
   // first entry into kInterpreterBytecodeRegister.
   __ LoadP(r3, FieldMemOperand(r4, JSFunction::kSharedFunctionInfoOffset));
@@ -828,9 +832,8 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   // Load accumulator, register file, bytecode offset, dispatch table into
   // registers.
   __ LoadRoot(kInterpreterAccumulatorRegister, Heap::kUndefinedValueRootIndex);
-  __ subi(kInterpreterRegisterFileRegister, fp,
-          Operand(2 * kPointerSize +
-                  StandardFrameConstants::kFixedFrameSizeFromFp));
+  __ addi(kInterpreterRegisterFileRegister, fp,
+          Operand(InterpreterFrameConstants::kRegisterFilePointerFromFp));
   __ mov(kInterpreterBytecodeOffsetRegister,
          Operand(BytecodeArray::kHeaderSize - kHeapObjectTag));
   __ LoadRoot(kInterpreterDispatchTableRegister,