Fork names were originally capitalized, and were made lower case by @narimiran
in commit 36a7519 to satisfy `parseEnum` in some tests. Restore the
capitalization and make the tests work with it.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Many places outside the EVM use `Fork` and the fork list, and in general we
want progressively fewer dependencies on EVM internal types and files.
This may prove to be a temporary location, especially when we implement
issue #640. But it's a fine temporary location if so.
Signed-off-by: Jamie Lokier <jamie@shareable.org>