Bug 1337112 - Remove links from JSRuntime to its single context and zone group, r=jandem,jonco.

ipc/testshell/XPCShellEnvironment.cpp

@@ -451,7 +451,7 @@ XPCShellEnvironment::Init()
     }
 
     JS::CompartmentOptions options;
-    options.creationOptions().setZone(JS::SystemZone);
+    options.creationOptions().setSystemZone();
     options.behaviors().setVersion(JSVERSION_LATEST);
     if (xpc::SharedMemoryEnabled())
         options.creationOptions().setSharedMemoryAndAtomicsEnabled(true);