SF/HWC2: Reorder makeCurrent to avoid deadlock

Now that we are deferring the release of FramebufferSurface buffers
(so that we can return a non-speculative fence), we end up holding
two acquired buffers during the call into HWComposer::commit (whereas
we previously would have only been holding one, with the other having
been released). This means that if the EGL implementation dequeues a
buffer as part of eglMakeCurrent, neither of the FramebufferSurface
buffers will be free, and the call to dequeueBuffer will block.

This change fixes that issue by reordering eglMakeCurrent to occur
after the deferred release.

Bug: 25684127
Change-Id: I6ec55b3f7b7d0e0f5be6029751cb086feeb52fbe