RFR: 8339507: appears to be causing 8GB build machines to hang

[hanklo6]

We generate each test randomly. The `asmtest.out.h` is currently around 100 KB. We have added the `--full` argument to allow users to create a complete test set.

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Commit messages:
 - Random generate test

Changes: https://git.openjdk.org/jdk/pull/21670/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21670&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339507
  Stats: 85065 lines in 2 files changed: 926 ins; 83631 del; 508 mod
  Patch: https://git.openjdk.org/jdk/pull/21670.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21670/head:pull/21670

PR: https://git.openjdk.org/jdk/pull/21670