[build] Fix and improve Java versions

test-utils/build.gradle.kts

@@ -1,3 +1,8 @@
 plugins {
 	java
 }
+
+java {
+	sourceCompatibility = JavaVersion.toVersion(libs.versions.java.test.get())
+	targetCompatibility = JavaVersion.toVersion(libs.versions.java.test.get())
+}