Issue 5177609: remove Monitor(Enter|Exit)Helper

Add necessary indirection for synchronized native methods that
lock/unlock the object/class using the regular JNI MonitorEnter/Exit
functions.

Change-Id: I00cda7284fcfa09e1218ddbfb1e24ea4aaa94ac3
diff --git a/src/assembler_x86.cc b/src/assembler_x86.cc
index b6183a9..693f1b4 100644
--- a/src/assembler_x86.cc
+++ b/src/assembler_x86.cc
@@ -1487,6 +1487,12 @@
   movl(dest.AsCpuRegister(), Address(base.AsCpuRegister(), offs));
 }
 
+void Assembler::LoadRawPtr(ManagedRegister dest, ManagedRegister base,
+                           Offset offs) {
+  CHECK(dest.IsCpuRegister() && dest.IsCpuRegister());
+  movl(dest.AsCpuRegister(), Address(base.AsCpuRegister(), offs));
+}
+
 void Assembler::LoadRawPtrFromThread(ManagedRegister dest, ThreadOffset offs) {
   CHECK(dest.IsCpuRegister());
   fs()->movl(dest.AsCpuRegister(), Address::Absolute(offs));