Vulkan: Improve usage of ErasePipelineCacheVkChunks method `ErasePipelineCacheVkChunks()` is now also used to erase any possibly trailing chunks from the current slot. This is done to free blob cache memory and to avoid parsing these chunks in the future and generating false-positive "chunk header corrupted" errors. Normally, new pipeline data is always larger than already saved, but in case of Vulkan driver update existing data may be ignored, so the cache data will be generated from scratch. This change will help erase old data from the blob cache. Bug: angleproject:42263322 Change-Id: I021abce40c4255b443babed87ed82b273d526ec0 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5854708 Reviewed-by: Charlie Lao <cclao@google.com> Commit-Queue: Igor Nazarov <i.nazarov@samsung.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>