[vm] Enable waitFor for 3.2 release

We are going to enable waitFor in 3.2 release
and disable it in 3.3.

This makes migration smoother for users that need
to use Isolate.resolvePackageUriSync which is
only added in 3.2.

The actual removal timeline remains the same:
we will remove waitFor in 3.4.

TEST=ci

Bug: #52121
Change-Id: I1ab7d07f874b3d914f070f1c358fcffaa96da28b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/329420
Reviewed-by: Martin Kustermann <[email protected]>
Commit-Queue: Slava Egorov <[email protected]>

CHANGELOG.md

@@ -71,16 +71,6 @@ constraint][language version] lower bound to 3.2 or greater (`sdk: '^3.2.0'`).
 
 - Added `broadcast` parameter to `Stream.empty` constructor.
 
-#### `dart:cli`
-
-- **Breaking change** [#52121][]:
-  - `waitFor` is disabled by default and slated for removal in 3.4. Attempting
-  to call this function will now throw an exception. Users that still depend
-  on `waitFor` can enable it by passing `--enable_deprecated_wait_for` flag
-  to the VM.
-
-[#52121]: https://github.com/dart-lang/sdk/issues/52121
-
 #### `dart:convert`
 
 - **Breaking change** [#52801][]:

runtime/vm/dart_api_impl.cc

@@ -84,7 +84,7 @@ DEFINE_FLAG(bool,
             "Dump common hash tables before snapshotting.");
 DEFINE_FLAG(bool,
             enable_deprecated_wait_for,
-            false,
+            true,
             "Enable deprecated dart:cli waitFor. "
             "This feature will be fully removed in Dart 3.4 release. "
             "See https://dartbug.com/52121.");