Remove --experimental-classes flag and related dead code.

src/arm/full-codegen-arm.cc

Index: src/arm/full-codegen-arm.cc
diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index 4146251d4d1a5f03b65b23061d3e90893d2d1280..8a8fe378df08764741b2994b4bb023d7235b12ee 100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -455,8 +455,7 @@ void FullCodeGenerator::EmitReturnSequence() {
     // sequence.
     { Assembler::BlockConstPoolScope block_const_pool(masm_);
       int32_t arg_count = info_->scope()->num_parameters() + 1;
-      if (FLAG_experimental_classes &&
-          IsSubclassConstructor(info_->function()->kind())) {
+      if (IsSubclassConstructor(info_->function()->kind())) {
         arg_count++;
       }
       int32_t sp_delta = arg_count * kPointerSize;
@@ -3189,15 +3188,7 @@ void FullCodeGenerator::VisitCall(Call* expr) {
       }
     }
   } else if (call_type == Call::SUPER_CALL) {
-    if (FLAG_experimental_classes) {
-      EmitSuperConstructorCall(expr);
-    } else {
-      EmitLoadSuperConstructor();
-      __ Push(result_register());
-      SuperReference* super_ref = callee->AsSuperReference();
-      VisitForStackValue(super_ref->this_var());
-      EmitCall(expr, CallICState::METHOD);
-    }
+    EmitSuperConstructorCall(expr);
   } else {
     DCHECK(call_type == Call::OTHER_CALL);
     // Call to an arbitrary expression not handled specially above.