"preparser" is a legacy test-suite written in Python. "cctest/test-parsing"
provides the same coverage and more for the preparser.

This CL removes "preparser" stand-alone test-suite

R=verwaest@chromium.org
CC=​machenbach@chromium.org

Bug: v8:10001
Change-Id: I1823967e654e8d6d9e42eadfd667f90074d57ba9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1926027Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Auto-Submit: Tamer Tas <tmrts@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65059}