[sil] Add another run of ARCSequenceOpts before inlining in function passes.

This eliminates some regressions by eliminating phase ordering in between
ARCSequenceOpts/inlining with read only functions whose read onlyness is lost
after inlining.

Author: meg-gupta

lib/SILOptimizer/PassManager/PassPipeline.cpp

@@ -344,6 +344,7 @@ void addFunctionPasses(SILPassPipelinePlan &P,
   // Run devirtualizer after the specializer, because many
   // class_method/witness_method instructions may use concrete types now.
   P.addDevirtualizer();
+  P.addARCSequenceOpts();
 
   // We earlier eliminated ownership if we are not compiling the stdlib. Now
   // handle the stdlib functions, re-simplifying, eliminating ARC as we do.