Fix locking a destroyed mutex.

Fix locking a destroyed mutex.

Surface should not lock the resource of a parent texture at destruction, because
it can already have been destroyed. For example when a texture's image was bound
as a render target, and the texture is deleted by the app, then the image holds
the last reference to the texture. When the render target image gets deleted, it
first releases its parent texture, and then the underlying surface gets
destroyed.

This is fixed by synchronizing, by locking and unlocking the (parent) resource,
earlier. The derived class is responsible for calling Surface::sync() before
releasing the parent resource.

Bug chromium:716803

Change-Id: Ifc3685dcf9e25e8419000af65d4bb7407f26bbcb
Reviewed-on: https://swiftshader-review.googlesource.com/9750
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>