Run regression testing in CI over openjdk20

[nrmancuso]

Since we are getting ready to support JDK 20 syntax (see #13279), we should run regression testing over the openjdk20 code base, as we have done for all other recent JDK versions.

We can use the script below:

#!/bin/bash
OUTPUT="test"
while  [ -n "$OUTPUT" ]; do
    OUTPUT=$(.ci/no-exception-test.sh openjdk20-with-checks-nonjavadoc-error | grep "Caused by: " | grep -oh '/.*.java' | sed 's./.[\\\\\\/].g' | uniq)
    echo "$OUTPUT"
    echo -e "<module name=\"BeforeExecutionExclusionFileFilter\">\n  <property name=\"fileNamePattern\" value=\"$OUTPUT\$\"/>\n</module>" >> config/projects-to-test/openjdk20-excluded.files
    rm -rf .ci-temp/contribution
    git add .
    git commit -m "added another file filter"
done

[rnveach]

Fix was merged