Configure toolchain locations when building PRs

This commit updates the script that builds PRs to add locations to the
installed JDK within the CI image. Without this change, PRs fail to
build because of the recently introduced JDK21 toolchain requirement in
the Spring Framework build.

Closes spring-projectsgh-30472

ci/scripts/build-pr.sh

@@ -4,5 +4,6 @@ set -e
 source $(dirname $0)/common.sh
 
 pushd git-repo > /dev/null
-./gradlew -Dorg.gradle.internal.launcher.welcomeMessageEnabled=false --no-daemon --max-workers=4 check
+./gradlew -Dorg.gradle.internal.launcher.welcomeMessageEnabled=false -Porg.gradle.java.installations.fromEnv=JDK17,JDK21 \
+  --no-daemon --max-workers=4 check
 popd > /dev/null