Update jtreg version for JDK21

[smlambert]

A recent change upstream requires us to update to jtreg 7.2 (where we are currently using jtreg 7.1.1).

See jtreg 7.2 change here openjdk/jdk@2763cf1

Also see any recent JDK21 OpenJDK test job:
https://ci.adoptium.net/job/Test_openjdk21_hs_sanity.openjdk_aarch64_linux/31/

[2023-04-27T00:11:04.876Z] TESTING:
[2023-04-27T00:11:04.876Z] Error: The testsuite at /home/jenkins/workspace/Test_openjdk21_hs_sanity.openjdk_aarch64_linux/aqa-tests/openjdk/openjdk-jdk/test/jdk requires jtreg version 7.2 b1 or higher and this is jtreg version 7.1.1-dev+1.

[sophia-guo]

jdk21 https://ci.adoptium.net/job/Test_openjdk21_hs_sanity.openjdk_aarch64_linux/36/, all other version works fine. Close it.

[smlambert]

Thanks @sophia-guo !