[dartdevc] Add missing FutureOr normalization

FutureOr<Object> --> Object
FutureOr<Object>? --> Object?

I don't believe this to be breaking because in the current SDK
nullable types do not yet exist, and we already landed the change
to normalize FutureOr of a top type. Right now Object is still
considered a top type.

Issue: #40611
Change-Id: I83cb06db9e4bca8cb9b2c041a044904eb1080d2e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/139031
Reviewed-by: Mark Zhou <[email protected]>
Reviewed-by: Sigmund Cherem <[email protected]>
Commit-Queue: Nicholas Shahan <[email protected]>

Author: nshahan

pkg/dev_compiler/lib/src/kernel/compiler.dart

@@ -2577,7 +2577,14 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
     if (typeArgument is InterfaceType &&
         typeArgument.classNode == _coreTypes.objectClass) {
       // Normalize FutureOr of Object, Object?, Object*.
-      normalizedType = typeArgument;
+      var nullable = futureOr.nullability == Nullability.nullable ||
+          typeArgument.nullability == Nullability.nullable;
+      var legacy = futureOr.nullability == Nullability.legacy ||
+          typeArgument.nullability == Nullability.legacy;
+      var nullability = nullable
+          ? Nullability.nullable
+          : legacy ? Nullability.legacy : Nullability.nonNullable;
+      normalizedType = typeArgument.withNullability(nullability);
     } else if (typeArgument is NeverType) {
       // FutureOr<Never> --> Future<Never>
       normalizedType = InterfaceType(

sdk_nnbd/lib/_internal/js_dev_runtime/private/ddc_runtime/classes.dart

@@ -140,8 +140,10 @@ normalizeFutureOr(typeConstructor, setBaseClass) {
     // Normalize raw FutureOr --> dynamic
     if (JS<bool>('!', '# == void 0', typeArg)) return _dynamic;
 
-    // FutureOr<dynamic|void|Object?|Object*> --> dynamic|void|Object?|Object*
+    // FutureOr<dynamic|void|Object?|Object*|Object> -->
+    //   dynamic|void|Object?|Object*|Object
     if (_isTop(typeArg) ||
+        _equalType(typeArg, Object) ||
         (_jsInstanceOf(typeArg, LegacyType) &&
             JS<bool>('!', '#.type === #', typeArg, Object))) {
       return typeArg;