[Gradle] Cover KT-50598 by tests

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/DifferentClassloadersIT.kt

@@ -38,15 +38,21 @@ class DifferentClassloadersIT : KGPBaseTest() {
             buildAndFail("publish", "-PmppProjectDependency=true") {
                 assertOutputContains(MULTIPLE_KOTLIN_PLUGINS_LOADED_WARNING)
             }
+
+            // check that the message is also printed on subsequent builds
+            buildAndFail("publish", "-PmppProjectDependency=true") {
+                assertOutputContains(MULTIPLE_KOTLIN_PLUGINS_LOADED_WARNING)
+            }
         }
     }
 
-    @DisplayName("KT-50598: Different classloaders message is only displayed on the first build")
+    @DisplayName("KT-50598: Different classloaders message can be disabled")
     @GradleTest
-    fun differentClassloadersOnlyFirstBuild(gradleVersion: GradleVersion) {
+    fun differentClassloadersWarningCanBeDisabled(gradleVersion: GradleVersion) {
         project("differentClassloaders", gradleVersion) {
             setupDifferentClassloadersProject()
 
+            fun checkThatWarningIsShown() {
                 build("-PmppProjectDependency=true") {
                     assertOutputContains(MULTIPLE_KOTLIN_PLUGINS_LOADED_WARNING)
 
@@ -55,6 +61,12 @@ class DifferentClassloadersIT : KGPBaseTest() {
 
                     assertEquals(setOf(":mpp-lib", ":jvm-app", ":js-app"), specificProjectsReported)
                 }
+            }
+
+            checkThatWarningIsShown()
+
+            // check that the message is also printed on subsequent builds
+            checkThatWarningIsShown()
 
             // Test the flag that turns off the warnings
             build("-PmppProjectDependency=true", "-Pkotlin.pluginLoadedInMultipleProjects.ignore=true") {