x86 interpreter fix

Correct the ordering of FP save prior to special subMode handling.
Also added a stress test mode to help catch this sort of problem in
the future.

Change-Id: I5bcd325858fa63023498bfd47e910aaf1530d6bb
diff --git a/vm/interp/Interp.cpp b/vm/interp/Interp.cpp
index f61f7ba..11e9408 100644
--- a/vm/interp/Interp.cpp
+++ b/vm/interp/Interp.cpp
@@ -1687,6 +1687,7 @@
     // Jit state that can change
     dvmJitUpdateThreadStateSingle(self);
 #endif
+    dvmInitializeInterpBreak(self);
 }
 
 /*
@@ -1708,6 +1709,10 @@
     if (gDvm.debuggerActive) {
         dvmEnableSubMode(thread, kSubModeDebuggerActive);
     }
+#if 0
+    // Debugging stress mode - force checkBefore
+    dvmEnableSubMode(thread, kSubModeCheckAlways);
+#endif
 }
 
 /*