[jdk17u-dev] RFR: 8304896: Update to use jtreg 7.2

[Goetz Lindenmaier]

I would like to update the jtreg requirement of 17u to jtreg 7.2

make/autoconf/lib-tests.m4
Change had to be applied to toolchange.m4

The rest hat to be resolved because 17 lists version
6+1. Trivial

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Commit messages:
 - Backport 2763cf14e6a174511ae8af471690ef18b10b3998

Changes: https://git.openjdk.org/jdk17u-dev/pull/1572/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1572&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304896
  Stats: 9 lines in 8 files changed: 0 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1572.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1572/head:pull/1572

PR: https://git.openjdk.org/jdk17u-dev/pull/1572