Initial import of JetStream v1.1

Upstream source: https://github.com/WebKit/WebKit/tree/main/Websites/browserbench.org/JetStream1.1

- Add webkit LICENSE file
- Add README.md

Bug: 340983089
Change-Id: I2d700122eb0698b523e0a80f3879b716b44c8f00
Reviewed-on: https://chromium-review.googlesource.com/c/external/github.com/WebKit/JetStream/+/5547901
Reviewed-by: John Chen <johnchen@chromium.org>
143 files changed