Use separate random number generator for each randomization pass

src/IceTargetLoweringMIPS32.cpp

Index: src/IceTargetLoweringMIPS32.cpp
diff --git a/src/IceTargetLoweringMIPS32.cpp b/src/IceTargetLoweringMIPS32.cpp
index a59f486c3aaec1cdbb510d4a083a9eda0690cb9a..685c8c09e097b5a8cb1f71a3a64d5e0da5220dbb 100644
--- a/src/IceTargetLoweringMIPS32.cpp
+++ b/src/IceTargetLoweringMIPS32.cpp
@@ -607,9 +607,10 @@ void TargetMIPS32::doAddressOptLoad() {
   UnimplementedError(Func->getContext()->getFlags());
 }
 
-void TargetMIPS32::randomlyInsertNop(float Probability) {
-  RandomNumberGeneratorWrapper RNG(Ctx->getRNG());
-  if (RNG.getTrueWithProbability(Probability)) {
+void TargetMIPS32::randomlyInsertNop(float Probability,
+                                     RandomNumberGenerator &RNG) {
+  RandomNumberGeneratorWrapper RNGW(RNG);
+  if (RNGW.getTrueWithProbability(Probability)) {
     UnimplementedError(Func->getContext()->getFlags());
   }
 }