Autogen support checks for draw_elements_base_vertex commands Also fixed command support conditions: * With an exception of MultiDrawElementsBaseVertexEXT, command and extension suffixes must match. Updated tests to account for that. * DrawElementsInstancedBaseVertex{EXT,OES} additionally require ES 3.0 or any of the instancing extensions. * DrawRangeElementsBaseVertex{EXT,OES} additionally require ES 3.0. Updated tests to account for that. * MultiDrawElementsBaseVertexEXT additionally requires GL_EXT_multi_draw_arrays. Bug: angleproject:409484297 Change-Id: I50b72ebc7d66128bcfd5671334094b7e90cb329c Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6524686 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Alexey Knyazev <lexa.knyazev@gmail.com>