.. and move all SharedFunctionInfo implementations from objects.cc to
the dedicated shared-function-info.cc.

Drive-by: Also move remaining JSRegExp impls.

Bug: v8:8888
Change-Id: I59adc3928f379eeb8b70f26d7e51d01c889c9a47
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2292240
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68832}