Fix RenderThread and worker thread names used by tools

Test: collected systrace and RenderThread hwuiTask1/2 shown
Change-Id: I1114ff72a7ed8c9dc86a64ebd15ca783d1b2ff08
diff --git a/libs/hwui/renderthread/RenderThread.cpp b/libs/hwui/renderthread/RenderThread.cpp
index 1f24f0e..3904ed2 100644
--- a/libs/hwui/renderthread/RenderThread.cpp
+++ b/libs/hwui/renderthread/RenderThread.cpp
@@ -329,7 +329,7 @@
 bool RenderThread::threadLoop() {
     setpriority(PRIO_PROCESS, 0, PRIORITY_DISPLAY);
     if (gOnStartHook) {
-        gOnStartHook();
+        gOnStartHook("RenderThread");
     }
     initThreadLocals();