RFR: 8292944: Noisy output when running make help the first time [v2]

[Magnus Ihse Bursie]

> From the bug report:
> Running make help after configuring produces a lot of noisy output from make before the actual help text is displayed.
> 
> Reproducer:
> 
> * bash ./configure --with-boot-jdk=... --with-devkit=...
> * make help
> 
> It only happens on the first invocation of make help, subsequent runs only display the actual help text. 
> 
> What happened was that the module-deps.gmk and find-test.gmk files where generated at an inopportune moment.
> 
> Note that this PR is dependent on https://github.com/openjdk/jdk/pull/23355 (I hope I got the Skara incantations right for that...)

Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:

  Add GENERATE_FIND_TESTS_FILE to RunTestPrebuilt as well

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/23357/files
  - new: https://git.openjdk.org/jdk/pull/23357/files/ac176e21..6bce53c2

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=23357&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23357&range=00-01

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/23357.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23357/head:pull/23357

PR: https://git.openjdk.org/jdk/pull/23357