Mark vertex attributes dirty during context switches gl::State::mDirtyCurrentValues is a second tier of gl::State::DIRTY_BIT_CURRENT_VALUES bit. Marking mDirtyCurrentValues dirty during context switches treats them in the same way as other gl::State::mDirtyBits are treated. This has regressed in https://chromium-review.googlesource.com/c/angle/angle/+/722423 where individual current values bits were squashed into one. Bug: chromium:920033 Change-Id: I778515f11c975f8d88bd2d8c08c49160fd011497 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1545009 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Yuly Novikov <ynovikov@chromium.org>