X87: [runtime] Unify comparison operator runtime entries.

  port 55b4df73(r34303)

  original commit message:
  Only use one set of %StrictEquals/%StrictNotEquals and
  %Equals/%NotEquals runtime entries for both the interpreter
  and the old-style CompareICStub. The long-term plan is to
  update the CompareICStub to also return boolean values, and
  even allow some more code sharing with the interpreter there.

BUG=

Review URL: https://codereview.chromium.org/1743123002

Cr-Commit-Position: refs/heads/master@{#34352}

src/x87/code-stubs-x87.cc

@@ -1150,21 +1150,26 @@ void CompareICStub::GenerateGeneric(MacroAssembler* masm) {
   }
   __ bind(&runtime_call);
 
+  if (cc == equal) {
+    {
+      FrameScope scope(masm, StackFrame::INTERNAL);
+      __ Push(edx);
+      __ Push(eax);
+      __ CallRuntime(strict() ? Runtime::kStrictEquals : Runtime::kEquals);
+    }
+    // Turn true into 0 and false into some non-zero value.
+    STATIC_ASSERT(EQUAL == 0);
+    __ sub(eax, Immediate(isolate()->factory()->true_value()));
+    __ Ret();
+  } else {
     // Push arguments below the return address.
     __ pop(ecx);
     __ push(edx);
     __ push(eax);
-
-  // Figure out which native to call and setup the arguments.
-  if (cc == equal) {
-    __ push(ecx);
-    __ TailCallRuntime(strict() ? Runtime::kStrictEquals : Runtime::kEquals);
-  } else {
     __ push(Immediate(Smi::FromInt(NegativeComparisonResult(cc))));
 
     // Restore return address on the stack.
     __ push(ecx);
-
     // Call the native; it returns -1 (less), 0 (equal), or 1 (greater)
     // tagged as a small integer.
     __ TailCallRuntime(Runtime::kCompare);