Create a job with a rake step that is to use the default rake installation and then run the job on a Windows agent that has one of the affected JREs in use. The job will fail with:

[workspace] $ rake.bat
'"C:\path\to\Jenkins\jobs\jobName\workspace\ruby.exe"' is not recognized as an internal or external command,
operable program or batch file.
Build step 'Invoke Rake' marked build as failure

This appears to be caused by JDK-8016721 : (process) Behavior of %~dp0 in .cmd and .bat scripts has changed whereby affected JRE versions try to create a sub-process with:

cmd  /c ""rake.bat""

...instead of:

cmd  /c rake.bat

...as previous versions of the JRE used to.

When configuring a non-default rake installation, the path to the batch file will be absolute and this seems to not break rake.bat.