[vm/compiler] Fix Handle passed to AllocateObject instruction while generating constructor tear-off

All handles passed to IL instructions should be ZoneHandles.
Recently added code for generating constructor tear-offs has been
passing Handle instead of ZoneHandle by mistake.

This change fixes the bug and adds assertions to AllocateObjectInstr so
it would check handle type earlier and on all platforms.

TEST=co19/LanguageFeatures/Constructor-tear-offs in debug/ia32 mode

Issue #46231

Change-Id: I99e6889e59bf40f4788a7f3c6d37dad89aa91ab0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/208686
Reviewed-by: Martin Kustermann <[email protected]>
Commit-Queue: Alexander Markov <[email protected]>

Author: alexmarkov

runtime/vm/compiler/backend/il.h

@@ -6171,6 +6171,8 @@ class AllocateObjectInstr : public AllocationInstr {
       : AllocationInstr(source, deopt_id),
         cls_(cls),
         type_arguments_(type_arguments) {
+    ASSERT(cls.IsZoneHandle());
+    ASSERT(!cls.IsNull());
     ASSERT((cls.NumTypeArguments() > 0) == (type_arguments != nullptr));
     if (type_arguments != nullptr) {
       SetInputAt(kTypeArgumentsPos, type_arguments);

runtime/vm/compiler/backend/redundancy_elimination_test.cc

@@ -219,7 +219,7 @@ static void TestAliasingViaRedefinition(
   const Library& lib =
       Library::Handle(LoadTestScript(script_chars, NoopNativeLookup));
 
-  const Class& cls = Class::Handle(
+  const Class& cls = Class::ZoneHandle(
       lib.LookupLocalClass(String::Handle(Symbols::New(thread, "K"))));
   const Error& err = Error::Handle(cls.EnsureIsFinalized(thread));
   EXPECT(err.IsNull());
@@ -383,7 +383,7 @@ static void TestAliasingViaStore(
   const Library& lib =
       Library::Handle(LoadTestScript(script_chars, NoopNativeLookup));
 
-  const Class& cls = Class::Handle(
+  const Class& cls = Class::ZoneHandle(
       lib.LookupLocalClass(String::Handle(Symbols::New(thread, "K"))));
   const Error& err = Error::Handle(cls.EnsureIsFinalized(thread));
   EXPECT(err.IsNull());

runtime/vm/compiler/frontend/kernel_to_il.cc

@@ -3450,7 +3450,7 @@ FlowGraph* FlowGraphBuilder::BuildGraphOfImplicitClosureFunction(
 
   // Push receiver.
   if (target.IsGenerativeConstructor()) {
-    const Class& cls = Class::Handle(Z, target.Owner());
+    const Class& cls = Class::ZoneHandle(Z, target.Owner());
     if (cls.NumTypeArguments() > 0) {
       if (!function.IsGeneric()) {
         Type& cls_type = Type::Handle(Z, cls.DeclarationType());