Vulkan: Add two tests for vertex conversion Two glBufferSubData calls and then use the buffer (get down to the vertex conversion code path, at least with forced fallback config). The test will exercise the logic regarding the conversion with multiple dirty ranges. Two tests are added in this CL, one with two overlapping range and another with non-overlapping range. Bug: b/357622380 Change-Id: Id8fa23a6e1511e2f03c002782ab99f167416ca02 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5805244 Reviewed-by: Yuxin Hu <yuxinhu@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Charlie Lao <cclao@google.com>