GraphicsEnvironment: Allow profileable apps to load layers

Apps that allow themselves to be profiled locally are also eligible
to load layers, since they are set dumpable. They can opt in by
setting the following in AndroidManifest.xml:

    <!-- App opts-in to being profiled by the shell -->
    <application>
        ...
        <profileable shell=”true”/>
    </application>

Bug: 128637647
Test: atest CtsGpuToolsHostTestCases
Test: Modify CtsGpuToolsHostTestCases to use profileable="true"
      and ensure loading from external works.

Change-Id: Ib072d07408c2abd8fee7179fec3a0d28d72d6398