Relax assert when applying a mixin application alias (fixes #25617).

tests/language/language.status

Index: tests/language/language.status
diff --git a/tests/language/language.status b/tests/language/language.status
index eb5262e80787a21bc98f0aebfb704f5057bc59e9..319fdb8251fc3d1c912e7b6a49387cfe7a319be4 100644
--- a/tests/language/language.status
+++ b/tests/language/language.status
@@ -97,13 +97,6 @@ disassemble_test: Pass, Fail # Issue 18122
 [ ($compiler == none || $compiler == precompiler) && ($runtime == vm || $runtime == dart_precompiled) && $arch == mips && $checked ]
 generic_instanceof3_test: Pass, Crash # Issue 17440.
 
-[ ($compiler == none || $compiler == precompiler) && ($runtime == vm || $runtime == dart_precompiled) && $mode == debug ]
-mixin_supertype_subclass3_test/01: Crash # Issue 25617
-mixin_supertype_subclass3_test/02: Crash # Issue 25617
-mixin_supertype_subclass3_test/03: Crash # Issue 25617
-mixin_supertype_subclass3_test/04: Crash # Issue 25617
-mixin_supertype_subclass3_test/05: Crash # Issue 25617
-
 [ ($compiler == none || $compiler == precompiler) && ($runtime == vm || $runtime == dart_precompiled) && $arch == mips && $mode == debug ]
 stack_overflow_test: Skip # Crashes. Issue 17440.
 stack_overflow_stacktrace_test: Skip # Crashes. Issue 17440.