Ensure jvmti agents don't share ThreadLocalStorage

Bug: 63665647
Test: ./test.py --host -j40

Change-Id: Iea33cca5b708f60390b8c79462ca991363ad33a2
diff --git a/runtime/openjdkjvmti/ti_thread.h b/runtime/openjdkjvmti/ti_thread.h
index 57967eb..d07dc06 100644
--- a/runtime/openjdkjvmti/ti_thread.h
+++ b/runtime/openjdkjvmti/ti_thread.h
@@ -54,6 +54,9 @@
   // To be called when it is safe to cache data.
   static void CacheData();
 
+  // Handle a jvmtiEnv going away.
+  static void RemoveEnvironment(jvmtiEnv* env);
+
   static jvmtiError GetAllThreads(jvmtiEnv* env, jint* threads_count_ptr, jthread** threads_ptr);
 
   static jvmtiError GetCurrentThread(jvmtiEnv* env, jthread* thread_ptr);