Use separate random number generator for each randomization pass

src/IceCfgNode.h

Index: src/IceCfgNode.h
diff --git a/src/IceCfgNode.h b/src/IceCfgNode.h
index e90969026a0dd78e5f09c995308a5ef442a40567..963638d0599428b2261aa5625f4ed05a969db0e9 100644
--- a/src/IceCfgNode.h
+++ b/src/IceCfgNode.h
@@ -91,7 +91,7 @@ public:
   void deletePhis();
   void advancedPhiLowering();
   void doAddressOpt();
-  void doNopInsertion();
+  void doNopInsertion(RandomNumberGenerator &RNG);
   void genCode();
   void livenessLightweight();
   bool liveness(Liveness *Liveness);