Check for spurious wake ups

Condition::wait() can spuriously wake up, so we must guard it with
another check to ensure that a given wake was truly due to having
been signaled.

Bug: 34592766
Test: Boot bullhead
Change-Id: Iaa5a0ca6186aea50c51e2c402ef95d7ba861be92
diff --git a/libs/hwui/renderthread/RenderThread.cpp b/libs/hwui/renderthread/RenderThread.cpp
index 9c10c4f..f383adc 100644
--- a/libs/hwui/renderthread/RenderThread.cpp
+++ b/libs/hwui/renderthread/RenderThread.cpp
@@ -345,7 +345,9 @@
 
     AutoMutex _lock(mutex);
     queue(&syncTask);
-    condition.wait(mutex);
+    while (!syncTask.hasRun()) {
+        condition.wait(mutex);
+    }
 }
 
 void RenderThread::queueAtFront(RenderTask* task) {