* 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/+/2447029Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>