This CL changes the existing TorqueError struct into a more general
TorqueMessage by adding a "kind" enum. The contextual for lint errors
is removed and replaced by a list of TorqueMessages.

A MessageBuilder is introduced to help with the different
combinations of present information and method of reporting. A lint
error with custom SourcePosition can be reported like this:

Lint("naming convention error").Position(<src_pos_var>);

While a fatal error, with CurrentSourcePosition can be thrown
like this:

Error("something went horrible wrong").Throw();

This approach is both backwards compatible and should prove flexible
enough to add more information to messages or add other message kinds.

Bug: v8:7793
Change-Id: Ib04fa188e34b3e8e9a6526a086f80da8f690a6f5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1617245
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61696}