Vulkan: updates to pipeline cache graph dumping logic 1. To dump pipeline cache graph you need to - 1. add "angle_dump_pipeline_cache_graph" compile time flag to args.gn 2. set Android property "angle.dump_pipeline_cache_graph" or envvar ANGLE_DUMP_PIPELINE_CACHE_GRAPH on non-Android platforms before app start 2. Default path for dump on Android is "/data/local/tmp/angle_dumps/" 3. "angle.pipeline_cache_graph_dump_path" Android property or envvar ANGLE_PIPELINE_CACHE_GRAPH_DUMP_PATH on non-Android platforms can be used to configure the dump path Bug: angleproject:6565 Change-Id: I38848aff58f413dd7bdffc9083116bd4b95e4960 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5226054 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: mohan maiya <m.maiya@samsung.com>