Clean up EGL thread state at thread exit in nanobench and DM

dm/DM.cpp

Index: dm/DM.cpp
diff --git a/dm/DM.cpp b/dm/DM.cpp
index f37fc8b7fff8eeab49ac62ce5f0a098580aacb03..c616e66cad94056ee19c75226d72dfcf8e05717a 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -1105,7 +1105,11 @@ int dm_main() {
 
     JsonWriter::DumpJson();  // It's handy for the bots to assume this is ~never missing.
     SkAutoGraphics ag;
+#if SK_SUPPORT_GPU
+    SkTaskGroup::Enabler enabled(FLAGS_threads, GrContextFactory::ReleaseGpuAPIsInThread);
+#else
     SkTaskGroup::Enabler enabled(FLAGS_threads);
+#endif
     gCreateTypefaceDelegate = &create_from_name;
 
     {
@@ -1183,6 +1187,11 @@ int dm_main() {
 
     print_status();
     SkDebugf("Finished!\n");
+
+#if SK_SUPPORT_GPU
+    // The main thread maybe ran GPU code.
+    GrContextFactory::ReleaseGpuAPIsInThread();
+#endif
     return 0;
 }