[Interpreter] Add support for parameter variables.

src/arm64/builtins-arm64.cc

Index: src/arm64/builtins-arm64.cc
diff --git a/src/arm64/builtins-arm64.cc b/src/arm64/builtins-arm64.cc
index 2539b4369e8390ec92b2bff14e2128b3db9a9518..d7394ff4032fcf9226a3e0e4b01db809ed0afd06 100644
--- a/src/arm64/builtins-arm64.cc
+++ b/src/arm64/builtins-arm64.cc
@@ -1025,9 +1025,11 @@ void Builtins::Generate_InterpreterExitTrampoline(MacroAssembler* masm) {
 
   // Leave the frame (also dropping the register file).
   __ LeaveFrame(StackFrame::JAVA_SCRIPT);
-  // Drop receiver + arguments.
-  // TODO(rmcilroy): Get number of arguments from BytecodeArray.
-  __ Drop(1, kXRegSize);
+
+  // Drop receiver + arguments and return.
+  __ Ldr(w1, FieldMemOperand(kInterpreterBytecodeArrayRegister,
+                             BytecodeArray::kParameterSizeOffset));
+  __ Drop(x1, 1);
   __ Ret();
 }