[Build] Fix configuration cache issue in KGP IT

`project` cannot be used at execution time.
^KTI-1433 Fixed

libraries/tools/kotlin-gradle-plugin-integration-tests/build.gradle.kts

@@ -341,6 +341,7 @@ tasks.withType<Test> {
     val jdk11Provider = project.getToolchainJdkHomeFor(JdkMajorVersion.JDK_11_0)
     val jdk16Provider = project.getToolchainJdkHomeFor(JdkMajorVersion.JDK_16_0)
     val jdk17Provider = project.getToolchainJdkHomeFor(JdkMajorVersion.JDK_17_0)
+    val jdk21Provider = project.getToolchainJdkHomeFor(JdkMajorVersion.JDK_21_0)
     val mavenLocalRepo = project.providers.systemProperty("maven.repo.local").orNull
 
     // Query required JDKs paths only on execution phase to avoid triggering auto-download on project configuration phase
@@ -352,12 +353,7 @@ tasks.withType<Test> {
         systemProperty("jdk11Home", jdk11Provider.get())
         systemProperty("jdk16Home", jdk16Provider.get())
         systemProperty("jdk17Home", jdk17Provider.get())
-        // jdk21Provider.isPresent throws NoToolchainAvailableException, so, we have to check for the exception
-        // Storing jdk21Provider in a field leads to "Configuration cache state could not be cached" error,
-        // since it tries to resolve the toolchain as well.
-        try {
-            systemProperty("jdk21Home", project.getToolchainJdkHomeFor(JdkMajorVersion.JDK_21_0).get())
-        } catch (_: NoToolchainAvailableException) {}
+        systemProperty("jdk21Home", jdk21Provider.get())
         if (mavenLocalRepo != null) {
             systemProperty("maven.repo.local", mavenLocalRepo)
         }