Rewrite the deserializer case macros to look, to formatters, more like
a single case value, and clean up some of the repetition to be more
explicit, e.g. replace

  SIXTEEN_CASES(kFoo)
    impl()

with

  case CASE_REPEAT(kFoo, 16):
    impl()

This should help with auto-formatting issues when modifying the big
deserializer switch statement.

As a drive-by, also clean up the per-space case macros to use a
function rather than a macro for specifying the bytecode, and add
helpers for encoding fixed raw data size in the bytecode (similar to
the existing helper for fixed repeat counts).

Change-Id: I885ba79afef03b95ad64cd78bdfba5dffc82be1e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2367853
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69635}