[vm] Suppress leak in Dart_SetVMFlags(...)
[vm] Suppress leak in Dart_SetVMFlags(...)

Flags parsing currently leaks string flag values
which is not a problem because users are not
expected to be calling SetVMFlags multiple times.

TEST=manually

Change-Id: Ie6e18a1142341b90c5345384a16b03a2947d69b4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/267361
Commit-Queue: Slava Egorov <72c81f38df725d8f1832acb9b5bb99563fc2f1b9@google.com>
Reviewed-by: Siva Annamalai <2e618a8cbd7bb6b3d4409061ae407d692a098546@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk