Skia Gold: Limit frame count on SwiftShader ANGLE traces have the ability to specify key frames for use in golden image comparison. Since software rendering is typically slow, we want to limit the impact of key frames on our CI time. Test: restricted_trace_gold_tests.py --key-frame-limit=10 Bug: b/449677825 Change-Id: Iddc26d76672b4cac36730eb1a4172f2037ccd3ef Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/7014647 Reviewed-by: Yuly Novikov <ynovikov@chromium.org> Commit-Queue: Cody Northrop <cnorthrop@google.com>