After test/jdk/java/util/TimeZone/CustomTzIDCheckDST.java testcase was integrated, it failed on the AIX platform.

By my investigation, "TZ=MEZ-1MESZ,M3.5.0,M10.5.0" timezone was changed to "Europe/Berlin" timezone on AIX platform.
It seems this situation is happened because older AIX did not support "MEZ-1MESZ,M3.5.0,M10.5.0" timezone by TZ environment variable.
https://www.ibm.com/support/pages/managing-time-zone-variable-posix
AIX special code was implemented into src/java.base/unix/native/libjava/TimeZone_md.c.
Current AIX supports "TZ=EST5EDT,M3.2.0/2:00:00,M11.1.0/2:00:00" style.
I think implementation change is required.

strftime() with "%z" does not return ISO 8601 format by default.
XPG_SUS_ENV=ON environment variable setting is required.
https://www.ibm.com/docs/en/aix/7.2?topic=s-strftime-strftime-l-subroutine
But XPG_SUS_ENV=ON is not supported by Hotspot.
(See src/hotspot/os/aix/os_aix.cpp)
Special code is required on this part.

Error output
==========================
STDERR:
 stdout: [];
 stderr: [Exception in thread "main" java.lang.RuntimeException: Got unexpected timezone information: Thu Aug 25 09:29:10 CEST 2022
        at CustomTzIDCheckDST.runTZTest(CustomTzIDCheckDST.java:71)
        at CustomTzIDCheckDST.main(CustomTzIDCheckDST.java:50)
]
==========================