Use separate random number generator for each randomization pass

src/IceTargetLoweringARM32.cpp

Index: src/IceTargetLoweringARM32.cpp
diff --git a/src/IceTargetLoweringARM32.cpp b/src/IceTargetLoweringARM32.cpp
index 14fa072ee0cec5386201c29c44d376d7a7826229..f0f904eb3217d3853e8d59f957e7b1a7ac549fde 100644
--- a/src/IceTargetLoweringARM32.cpp
+++ b/src/IceTargetLoweringARM32.cpp
@@ -2505,9 +2505,10 @@ void TargetARM32::doAddressOptLoad() {
   UnimplementedError(Func->getContext()->getFlags());
 }
 
-void TargetARM32::randomlyInsertNop(float Probability) {
-  RandomNumberGeneratorWrapper RNG(Ctx->getRNG());
-  if (RNG.getTrueWithProbability(Probability)) {
+void TargetARM32::randomlyInsertNop(float Probability,
+                                    RandomNumberGenerator &RNG) {
+  RandomNumberGeneratorWrapper RNGW(RNG);
+  if (RNGW.getTrueWithProbability(Probability)) {
     UnimplementedError(Func->getContext()->getFlags());
   }
 }