s390: Remove experiment for restricting constructor return values

Port 813094ac

Original Commit Message:

    This is not web compatible, so let's delete the code.

R=gsathya@chromium.org, joransiu@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: I8cbe561b176c25900d4e40eb8912e5c0b4c44410
Reviewed-on: https://chromium-review.googlesource.com/1069170Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#53290}

src/builtins/s390/builtins-s390.cc

@@ -249,9 +249,10 @@ void Generate_JSBuiltinsConstructStubHelper(MacroAssembler* masm) {
   __ Ret();
 }
 
+}  // namespace
+
 // The construct stub for ES5 constructor functions and ES6 class constructors.
-void Generate_JSConstructStubGeneric(MacroAssembler* masm,
-                                     bool restrict_constructor_return) {
+void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  --      r2: number of arguments (untagged)
   //  --      r3: constructor function
@@ -383,7 +384,7 @@ void Generate_JSConstructStubGeneric(MacroAssembler* masm,
     // If the result is an object (in the ECMA sense), we should get rid
     // of the receiver and use the result; see ECMA-262 section 13.2.2-7
     // on page 74.
-    Label use_receiver, do_throw, other_result, leave_frame;
+    Label use_receiver, do_throw, leave_frame;
 
     // If the result is undefined, we jump out to using the implicit receiver.
     __ JumpIfRoot(r2, Heap::kUndefinedValueRootIndex, &use_receiver);
@@ -392,26 +393,15 @@ void Generate_JSConstructStubGeneric(MacroAssembler* masm,
     // is a valid receiver.
 
     // If the result is a smi, it is *not* an object in the ECMA sense.
-    __ JumpIfSmi(r2, &other_result);
+    __ JumpIfSmi(r2, &use_receiver);
 
     // If the type of the result (stored in its map) is less than
     // FIRST_JS_RECEIVER_TYPE, it is not an object in the ECMA sense.
     STATIC_ASSERT(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
     __ CompareObjectType(r2, r6, r6, FIRST_JS_RECEIVER_TYPE);
     __ bge(&leave_frame);
+    __ b(&use_receiver);
 
-    __ bind(&other_result);
-    // The result is now neither undefined nor an object.
-    if (restrict_constructor_return) {
-      // Throw if constructor function is a class constructor
-      __ LoadP(r6, MemOperand(fp, ConstructFrameConstants::kConstructorOffset));
-      __ LoadP(r6, FieldMemOperand(r6, JSFunction::kSharedFunctionInfoOffset));
-      __ LoadlW(r6, FieldMemOperand(r6, SharedFunctionInfo::kFlagsOffset));
-      __ TestBitMask(r6, SharedFunctionInfo::IsClassConstructorBit::kMask, r0);
-      __ beq(&use_receiver);
-    } else {
-      __ b(&use_receiver);
-    }
     __ bind(&do_throw);
     __ CallRuntime(Runtime::kThrowConstructorReturnedNonObject);
 
@@ -435,16 +425,7 @@ void Generate_JSConstructStubGeneric(MacroAssembler* masm,
   __ AddP(sp, sp, Operand(kPointerSize));
   __ Ret();
 }
-}  // namespace
 
-void Builtins::Generate_JSConstructStubGenericRestrictedReturn(
-    MacroAssembler* masm) {
-  Generate_JSConstructStubGeneric(masm, true);
-}
-void Builtins::Generate_JSConstructStubGenericUnrestrictedReturn(
-    MacroAssembler* masm) {
-  Generate_JSConstructStubGeneric(masm, false);
-}
 void Builtins::Generate_JSBuiltinsConstructStub(MacroAssembler* masm) {
   Generate_JSBuiltinsConstructStubHelper(masm);
 }
@@ -2402,7 +2383,7 @@ void Builtins::Generate_ConstructFunction(MacroAssembler* masm) {
           RelocInfo::CODE_TARGET);
 
   __ bind(&call_generic_stub);
-  __ Jump(masm->isolate()->builtins()->JSConstructStubGeneric(),
+  __ Jump(BUILTIN_CODE(masm->isolate(), JSConstructStubGeneric),
           RelocInfo::CODE_TARGET);
 }