This unifies functionality between release-mode ShortPrint and
debug-mode Print:

- Prefixes and suffixes are now consistent. 'u' for two-byte, '#' for
  internalized, 'c' for cons, '>' for thin.
- Logic was simplified and is now based on 3 functions:
  PrefixForDebugPrint, PrintUC16, SuffixForDebugPrint.
- %DebugPrint no longer interprets strings as 'code markers'.
- The ancient and unused use_verbose_printer flag was removed.

Bug: v8:10581
Change-Id: Iebc6a746a2683f9f5a8ef60579836e7f66a188fa
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2224868Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68103}