RFR: 8269259: Remove obsolete apps, tests, and scripts

[Kevin Rushforth]

This PR deletes the following applications, tests, and scripts that are either obsolete 
or unmaintained:

apps/performance/*

apps/tests/HelloTest

apps/toys/FXSlideShow
apps/toys/Industrial
apps/toys/Shape3DToy
apps/toys/StretchyGrid
apps/toys/TouchSuite

tests/functional/*
tests/performance/VMPerformance

tools/*

See the JBS issue and [this thread](https://mail.openjdk.java.net/pipermail/openjfx-dev/2021-June/030894.html) on the openjfx-dev mailing list for more info.

There are two commits for ease of review. The first one is generated by doing a "git rm -r" on each of the above listed directories. The second is to remove any remaining references to the removed directories.

-------------

Commit messages:
 - Remove references to removed dirs and apps
 - 8269259: Remove obsolete apps, tests, and scripts

Changes: https://git.openjdk.java.net/jfx/pull/545/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=545&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8269259
  Stats: 33646 lines in 196 files changed: 0 ins; 33645 del; 1 mod
  Patch: https://git.openjdk.java.net/jfx/pull/545.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/545/head:pull/545

PR: https://git.openjdk.java.net/jfx/pull/545