FrameCapture: More fixes for app updates * Disable GL_EXT_map_buffer_range during capture, several native GLES drivers do not support it. * Unmap buffers before updating them during Reset. Some native drivers require it. Test: Temple Run on multiple systems Bug: angleproject:4845 Change-Id: I9aea9c220320095aee87da107320b8fcad6c0a2f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2447029 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>