[PM] Fix new PM to perform SpeculativeExecution as in old PM

[dfukalov]

Summary

Old PM runs SpeculativeExecutionPass for targets that have divergent branches.
It uses createSpeculativeExecutionIfHasBranchDivergencePass that creates
the pass with OnlyIfDivergentTarget=true, whereas new PM just created the
pass with default OnlyIfDivergentTarget=fase so it unexpectedly runs and
causes buildbot test fails.

llvm/lib/Passes/PassBuilder.cpp

PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
 
   // Global value numbering based sinking.
   if (EnableGVNSink) {
     FPM.addPass(GVNSinkPass());
     FPM.addPass(SimplifyCFGPass());
   }
 
   // Speculative execution if the target has divergent branches; otherwise nop.
-  FPM.addPass(SpeculativeExecutionPass());
+  FPM.addPass(SpeculativeExecutionPass(/* OnlyIfDivergentTarget =*/true));
 
   // Optimize based on known information about branches, and cleanup afterward.
   FPM.addPass(JumpThreadingPass());
   FPM.addPass(CorrelatedValuePropagationPass());
 
   FPM.addPass(SimplifyCFGPass());
   if (Level == OptimizationLevel::O3)
     FPM.addPass(AggressiveInstCombinePass());