RFR: 8238434: Ensemble: Update version of Lucene to 7.7.2

[Kevin Rushforth]

Update the version of Lucene used by Ensemble to the latest release of Lucene 7 which is version 7.7.2.

Per the instructions in [`UPDATING-lucene.txt`](https://github.com/openjdk/jfx/blob/master/apps/samples/Ensemble8/UPDATING-lucene.txt), I made the following chages:

1. Bumped the version numbers from 7.7.1 to 7.7.2 in all needed places
2. Regenerated the index files. I used JDK 11.x to do this (out of an abundance of caution, not because I think it matters).

To test this: apply the patch, run `gradle apps`, launch Ensemble8, and search for a sample or JavaFX component in the upper-right search box.

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

Commits:
 - efb46435: 8238434: Ensemble: Update version of Lucene to 7.7.2

Changes: https://git.openjdk.java.net/jfx/pull/105/files
 Webrev: https://webrevs.openjdk.java.net/jfx/105/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8238434
  Stats: 10 lines in 10 files changed: 0 ins; 0 del; 10 mod
  Patch: https://git.openjdk.java.net/jfx/pull/105.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/105/head:pull/105

PR: https://git.openjdk.java.net/jfx/pull/105