Delete obsolete debug stub

runtime/vm/stub_code_mips.cc

Index: runtime/vm/stub_code_mips.cc
===================================================================
--- runtime/vm/stub_code_mips.cc	(revision 31677)
+++ runtime/vm/stub_code_mips.cc	(working copy)
@@ -2106,23 +2106,6 @@
 }
 
 
-//  V0: return value.
-void StubCode::GenerateBreakpointReturnStub(Assembler* assembler) {
-  __ TraceSimMsg("BreakpoingReturnStub");
-  // Create a stub frame as we are pushing some objects on the stack before
-  // calling into the runtime.
-  __ EnterStubFrame();
-  __ Push(V0);
-  __ CallRuntime(kBreakpointReturnHandlerRuntimeEntry, 0);
-  __ Pop(V0);
-  __ LeaveStubFrame();
-
-  // Instead of returning to the patched Dart function, emulate the
-  // smashed return code pattern and return to the function's caller.
-  __ LeaveDartFrameAndReturn();
-}
-
-
 //  RA: return address (Dart code).
 //  S5: Inline cache data array.
 void StubCode::GenerateBreakpointDynamicStub(Assembler* assembler) {