[strong] Refactor ObjectStrength into a replacement for strong boolean args

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index f24ae4d725bc1d4dfe3e3c93a0219d2575593692..48a2a885ed885fb2e2ec9e8ced9f63f2bdbb4def 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -1566,7 +1566,7 @@ void CompareICStub::GenerateGeneric(MacroAssembler* masm) {
       // Check for undefined.  undefined OP undefined is false even though
       // undefined == undefined.
       __ CompareRoot(rdx, Heap::kUndefinedValueRootIndex);
-      if (strong()) {
+      if (is_strong(strength())) {
         // In strong mode, this comparison must throw, so call the runtime.
         __ j(equal, &runtime_call, Label::kFar);
       } else {
@@ -1594,7 +1594,7 @@ void CompareICStub::GenerateGeneric(MacroAssembler* masm) {
       // Call runtime on identical symbols since we need to throw a TypeError.
       __ cmpb(rcx, Immediate(static_cast<uint8_t>(SYMBOL_TYPE)));
       __ j(equal, &runtime_call, Label::kFar);
-      if (strong()) {
+      if (is_strong(strength())) {
         // We have already tested for smis and heap numbers, so if both
         // arguments are not strings we must proceed to the slow case.
         __ testb(rcx, Immediate(kIsNotStringMask));
@@ -1785,7 +1785,8 @@ void CompareICStub::GenerateGeneric(MacroAssembler* masm) {
   if (cc == equal) {
     builtin = strict() ? Builtins::STRICT_EQUALS : Builtins::EQUALS;
   } else {
-    builtin = strong() ? Builtins::COMPARE_STRONG : Builtins::COMPARE;
+    builtin =
+        is_strong(strength()) ? Builtins::COMPARE_STRONG : Builtins::COMPARE;
     __ Push(Smi::FromInt(NegativeComparisonResult(cc)));
   }
 
@@ -3610,7 +3611,7 @@ void CompareICStub::GenerateNumbers(MacroAssembler* masm) {
 
   __ bind(&unordered);
   __ bind(&generic_stub);
-  CompareICStub stub(isolate(), op(), strong(), CompareICState::GENERIC,
+  CompareICStub stub(isolate(), op(), strength(), CompareICState::GENERIC,
                      CompareICState::GENERIC, CompareICState::GENERIC);
   __ jmp(stub.GetCode(), RelocInfo::CODE_TARGET);