Remove strong mode support from count operations.

src/full-codegen/x64/full-codegen-x64.cc

Index: src/full-codegen/x64/full-codegen-x64.cc
diff --git a/src/full-codegen/x64/full-codegen-x64.cc b/src/full-codegen/x64/full-codegen-x64.cc
index e63d3cd07a3be26842423251e5827134a87b0027..d65ab33ebc31764e225cf9c5a40f5e085b573e42 100644
--- a/src/full-codegen/x64/full-codegen-x64.cc
+++ b/src/full-codegen/x64/full-codegen-x64.cc
@@ -3580,11 +3580,11 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
     __ jmp(&stub_call, Label::kNear);
     __ bind(&slow);
   }
-  if (!is_strong(language_mode())) {
-    ToNumberStub convert_stub(isolate());
-    __ CallStub(&convert_stub);
-    PrepareForBailoutForId(expr->ToNumberId(), TOS_REG);
-  }
+
+  // Convert old value into a number.
+  ToNumberStub convert_stub(isolate());
+  __ CallStub(&convert_stub);
+  PrepareForBailoutForId(expr->ToNumberId(), TOS_REG);
 
   // Save result for postfix expressions.
   if (expr->is_postfix()) {
@@ -3624,9 +3624,6 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
   patch_site.EmitPatchInfo();
   __ bind(&done);
 
-  if (is_strong(language_mode())) {
-    PrepareForBailoutForId(expr->ToNumberId(), TOS_REG);
-  }
   // Store the value returned in rax.
   switch (assign_type) {
     case VARIABLE: