fixup! Fix console-related test failures on JDK 22

Fix for builds that don't have explicit javaToolchainVersion Note that
in GitHub workflows, only cross-version.yml uses -PjavaToolchainVersion
explicitly.

An alternative would be to do something like what plugin
junitbuild.java-toolchain-conventions.gradle.kts does, quote:

	val defaultLanguageVersion = JavaLanguageVersion.of(17)
	val javaLanguageVersion = buildParameters.javaToolchainVersion.map { JavaLanguageVersion.of(it) }.getOrElse(defaultLanguageVersion)

Or to refactor the build parameter javaToolchainVersion to have a
default value:

	integer("javaToolchainVersion") {
		description = "Defines the Java toolchain version to use for compiling code"
		defaultValue = 17
	}

gradle/plugins/common/src/main/kotlin/junitbuild.testing-conventions.gradle.kts

@@ -51,7 +51,7 @@ tasks.withType<Test>().configureEach {
 			"-XX:FlightRecorderOptions=stackdepth=1024"
 		)
 	}
-	if (buildParameters.javaToolchainVersion.get() >= 22) {
+	if (buildParameters.javaToolchainVersion.isPresent && buildParameters.javaToolchainVersion.get() >= 22) {
 		jvmArgs("-Djdk.console=java.base")
 	}