opengl translator: conformance fixes

- fix destructor of eglcontext to delete its share group if needed
- fix available eglconfigs not to choose configs with BUFFER_SIZE=0
  or configs which do not support RGBA
- fix conformant bit on eglconfig
- fix typo in glBindBuffer
- fix glVertexAttribPointer to send correct offset to GL with vbo

Change-Id: I69d980407a40cb371ec62c5c883e4190bdcfce72
7 files changed