Also generate a corpus to unblock the Chromium roll. The build tools
expect there to be a corresponding directory somewhere.
Bug: 275
Change-Id: I7a061ba6625ec57c10b0ae17e68b6b0159c539d4
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/46826
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>