Review fixes

Author: dkhalanskyjb

kotlinx-coroutines-test/common/src/TestScope.kt

@@ -251,6 +251,8 @@ internal class TestScopeImpl(context: CoroutineContext) :
     /** Called at the end of the test. May only be called once. Returns the list of caught unhandled exceptions. */
     fun leave(): List<Throwable> = synchronized(lock) {
         check(entered && !finished)
+        /** After [finished] becomes `true`, it is no longer valid to have [reportException] as the callback. */
+        ExceptionCollector.removeOnExceptionCallback(lock)
         finished = true
         uncaughtExceptions
     }

kotlinx-coroutines-test/jvm/src/module-info.java

@@ -1,4 +1,6 @@
+import kotlinx.coroutines.CoroutineExceptionHandler;
 import kotlinx.coroutines.internal.MainDispatcherFactory;
+import kotlinx.coroutines.test.internal.ExceptionCollectorAsService;
 import kotlinx.coroutines.test.internal.TestMainDispatcherFactory;
 
 module kotlinx.coroutines.test {
@@ -8,4 +10,5 @@
     exports kotlinx.coroutines.test;
 
     provides MainDispatcherFactory with TestMainDispatcherFactory;
+    provides CoroutineExceptionHandler with ExceptionCollectorAsService;
 }