Use ANDROID_get_native_client_buffer in HWUI

ReliableSurface still needs AHardwareBuffer_to_ANativeWindowBuffer to
safely convert to an ANativeWindowBuffer to interop with the
interception methods, but when converting to EGLClientBuffer the EGL
extension should be used instead.

Bug: 152802621
Test: builds, boots
Change-Id: I49cfeee4d7e5d4e793891771686c2286d4ac79af