Add counters for requested/inserted/executed soft deopts

src/deoptimizer.cc

Index: src/deoptimizer.cc
diff --git a/src/deoptimizer.cc b/src/deoptimizer.cc
index be0ea98b52e5a554c40445bc85c4ae35fc743aa6..e4475538e18e4b052b5559d28fd225652aeb03cd 100644
--- a/src/deoptimizer.cc
+++ b/src/deoptimizer.cc
@@ -547,6 +547,7 @@ Deoptimizer::Deoptimizer(Isolate* isolate,
   if (function != NULL && function->IsOptimized()) {
     function->shared()->increment_deopt_count();
     if (bailout_type_ == Deoptimizer::SOFT) {
+      isolate->counters()->soft_deopts_executed()->Increment();
       // Soft deopts shouldn't count against the overall re-optimization count
       // that can eventually lead to disabling optimization for a function.
       int opt_count = function->shared()->opt_count();