Move thread flags and state into 32bits.

We need to ensure that transitions to Runnable are atomic wrt to a
thread modifying the suspend count. Currently this is achieved by
holding the thread_suspend_count_lock_. This change creates a set of bit
flags that summarize that the suspend_count_ is raised and also others
flags that signify the managed code should go into a slow path.

The effect of this change are two-fold:
1) transitions from suspended to runnable can CAS the thread state
rather than holding the suspend_count_lock_. This will make JNI
transitions cheaper.
2) the exception/suspend/interpreter poll needed for shadow frames can
be rolled into a single compare of the bit fields against 0.

Change-Id: I589f84e3dca396c3db448bf32d814565acf3d11f
diff --git a/src/compiler/codegen/MethodCodegenDriver.cc b/src/compiler/codegen/MethodCodegenDriver.cc
index 8269f8b..7227487 100644
--- a/src/compiler/codegen/MethodCodegenDriver.cc
+++ b/src/compiler/codegen/MethodCodegenDriver.cc
@@ -260,22 +260,9 @@
     case Instruction::NOP:
       break;
 
-    case Instruction::MOVE_EXCEPTION: {
-      int exOffset = Thread::ExceptionOffset().Int32Value();
-      rlResult = oatEvalLoc(cUnit, rlDest, kCoreReg, true);
-#if defined(TARGET_X86)
-      newLIR2(cUnit, kX86Mov32RT, rlResult.lowReg, exOffset);
-      newLIR2(cUnit, kX86Mov32TI, exOffset, 0);
-#else
-      int resetReg = oatAllocTemp(cUnit);
-      loadWordDisp(cUnit, rSELF, exOffset, rlResult.lowReg);
-      loadConstant(cUnit, resetReg, 0);
-      storeWordDisp(cUnit, rSELF, exOffset, resetReg);
-      oatFreeTemp(cUnit, resetReg);
-#endif
-      storeValue(cUnit, rlDest, rlResult);
+    case Instruction::MOVE_EXCEPTION:
+      genMoveException(cUnit, rlDest);
       break;
-    }
     case Instruction::RETURN_VOID:
       if (!(cUnit->attrs & METHOD_IS_LEAF)) {
         genSuspendTest(cUnit, optFlags);