RFR: 8347831: Re-examine version check when cross linking [v5]

[Henry Jen]

> This PR include build changes from @magicus and jlink change to verify the build signature.
> 
> Tested with local builds for MacOS and Linux as below shows that cross linking with same build is working while linking with different build failed with error message.
> 
> ❯ export JAVA_HOME=./build/macosx-x86_64-server-fastdebug/images/jdk-bundle/jdk-26.jdk/Contents/Home
>                                                                                                                                                                  
> ❯ java --version
> openjdk 26-internal 2026-03-17
> OpenJDK Runtime Environment (fastdebug build 26-internal-adhoc.hjen.JDK-8347831)
> OpenJDK 64-Bit Server VM (fastdebug build 26-internal-adhoc.hjen.JDK-8347831, mixed mode, sharing)
>                                                                                                                                                                  
> ❯ jlink --version                                                                       
> 26-internal
>                                                                                                                                                                  
> ❯ jlink --module-path ./build/linux-x86_64-server-release/images/jdk/jmods --add-modules java.base --output linux                                                                                                                                        
>                                                                                                                                                                  
> ❯ jlink --add-modules java.base --output macos
>                                                             
> ❯ jlink --module-path ~/linux/jdk-25.0.1/jmods --add-modules java.base --output linux25    
> Error: jlink build N/A-26-internal-adhoc.hjen.JDK-8347831-2026-03-17 does not match target java.base build N/A
>                                                                                                                                                                  
> ❯ jlink --module-path /Library/Java/JavaVirtualMachines/jdk-25.jdk/Contents/Home/jmods --add-modules java.base --output macos25 
> Error: jlink build N/A-26-internal-adhoc.hjen.JDK-8347831-2026-03-17 does not match target java.base build N/A

Henry Jen has updated the pull request incrementally with one additional commit since the last revision:

  Treat missing release.txt as emptry release signature

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/28155/files
  - new: https://git.openjdk.org/jdk/pull/28155/files/68584d93..0f1c9351

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28155&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28155&range=03-04

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/28155.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28155/head:pull/28155

PR: https://git.openjdk.org/jdk/pull/28155