Move more logic into the {TraceLine} class. In release builds, this
class will not do anything. Since there is no code after the switch in
{DecodeOp} any more after this CL, we can apply tail-call optimization
(via explicit returns in C++), which will save an additional call in
some cases.

R=thibaudm@chromium.org

Bug: v8:10576
Change-Id: Ie11ec550ab33d0c03a27375f34576e3a75dcf6ad
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2254021Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68515}