kotlin script template tests are broken on Java 19

[bclozel]

When running org.springframework.web.reactive.result.view.script.KotlinScriptTemplateTests on Java 19, we're getting the following failure:

Failed to evaluate script [org/springframework/web/reactive/result/view/script/kotlin/render.kts]
java.lang.IllegalStateException: Failed to evaluate script [org/springframework/web/reactive/result/view/script/kotlin/render.kts]
	at org.springframework.web.reactive.result.view.script.ScriptTemplateView.loadScripts(ScriptTemplateView.java:302)
	at org.springframework.web.reactive.result.view.script.ScriptTemplateView.createEngineFromName(ScriptTemplateView.java:276)
	at org.springframework.web.reactive.result.view.script.ScriptTemplateView.setApplicationContext(ScriptTemplateView.java:241)
	at org.springframework.web.reactive.result.view.script.KotlinScriptTemplateTests.createViewWithUrl(KotlinScriptTemplateTests.java:91)
	at org.springframework.web.reactive.result.view.script.KotlinScriptTemplateTests.render(KotlinScriptTemplateTests.java:78)
	at org.springframework.web.reactive.result.view.script.KotlinScriptTemplateTests.renderTemplateWithFrenchLocale(KotlinScriptTemplateTests.java:48)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
	at java.base/java.lang.reflect.Method.invoke(Method.java:578)
	at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:727)
	at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
	at 
...
org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:71)
	at worker.org.gradle.process.internal.worker.GradleWorkerMain.run(GradleWorkerMain.java:69)
	at worker.org.gradle.process.internal.worker.GradleWorkerMain.main(GradleWorkerMain.java:74)
Caused by: javax.script.ScriptException: ERROR Cannot inline bytecode built with JVM target 17 into bytecode that is being built with JVM target 1.8. Please specify proper '-jvm-target' option (ScriptingHost574059d5_Line_0.kts:11:58)
	at org.jetbrains.kotlin.cli.common.repl.KotlinJsr223JvmScriptEngineBase.asJsr223EvalResult(KotlinJsr223JvmScriptEngineBase.kt:104)
	at org.jetbrains.kotlin.cli.common.repl.KotlinJsr223JvmScriptEngineBase.compileAndEval(KotlinJsr223JvmScriptEngineBase.kt:63)
	at kotlin.script.experimental.jvmhost.jsr223.KotlinJsr223ScriptEngineImpl.compileAndEval(KotlinJsr223ScriptEngineImpl.kt:95)
	at org.jetbrains.kotlin.cli.common.repl.KotlinJsr223JvmScriptEngineBase.eval(KotlinJsr223JvmScriptEngineBase.kt:33)
	at java.scripting/javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:247)
	at org.springframework.web.reactive.result.view.script.ScriptTemplateView.loadScripts(ScriptTemplateView.java:299)
	... 87 more

This can be reproduced by running ./gradlew :spring-webflux:check -PtestToolchain=19.
The same tests don't fail with Java 18, so this might be that Java 19 support is not there yet and it falls back to Java 1.8. Our toolchain configuration can be found here.

[bclozel]

We need to revert 7dd6afc when this is solved.

[sdeleuze]

I think Kotlin 1.8 brings Java 19 support so I move this issue to 6.1 along to #29754.