Enable context dropping on stopped only

Fixes: 245565051
Test: open calculator, hit home, wait 10s, dumpsys & verify no GL
context

Change-Id: I34566a566829c00c983ed6da78f71d8a8238c337

libs/hwui/MemoryPolicy.h

@@ -53,8 +53,8 @@ struct MemoryPolicy {
     // Whether or not to only purge scratch resources when triggering UI Hidden or background
     // collection
     bool purgeScratchOnly = true;
-    // EXPERIMENTAL: Whether or not to trigger releasing GPU context when all contexts are stopped
-    bool releaseContextOnStoppedOnly = false;
+    // Whether or not to trigger releasing GPU context when all contexts are stopped
+    bool releaseContextOnStoppedOnly = true;
 };
 
 const MemoryPolicy& loadMemoryPolicy();