Add separate test project for warn on different classloaders test

After this update  to have different classpath hash in subprojects,
they should have different sets of plugins applied. But KGP could be
in all of them.

^KT-49227 In Progress

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

@@ -998,7 +998,7 @@ class KotlinGradleIT : BaseGradleIT() {
     }
 
     @Test
-    fun testDetectingDifferentClassLoaders() = with(Project("kt-27059-pom-rewriting", GradleVersionRequired.FOR_MPP_SUPPORT)) {
+    fun testDetectingDifferentClassLoaders() = with(Project("differentClassloaders", GradleVersionRequired.FOR_MPP_SUPPORT)) {
         setupWorkingDir()
 
         val originalRootBuildScript = gradleBuildScript().readText()

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/differentClassloaders/build.gradle

@@ -0,0 +1,10 @@
+plugins {
+    id "org.jetbrains.kotlin.multiplatform" version "<pluginMarkerVersion>" apply false
+}
+
+allprojects {
+    repositories {
+        mavenLocal()
+        mavenCentral()
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/differentClassloaders/gradle.properties

@@ -0,0 +1 @@
+kotlin.js.compiler=legacy

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/differentClassloaders/js-app/build.gradle

@@ -0,0 +1,41 @@
+plugins {
+    id "kotlin2js"
+    id "maven-publish"
+    id "org.jetbrains.kotlin.plugin.serialization"
+}
+
+group = "com.example"
+version = "1.0"
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-js"
+}
+
+if (project.findProperty("mppProjectDependency") == "true") {
+
+    dependencies {
+        api project(":mpp-lib")
+    }
+
+} else {
+
+    repositories {
+        maven { setUrl "${rootProject.buildDir}/repo" }
+    }
+
+    dependencies {
+        api "com.example:mpp-lib:1.0"
+    }
+
+}
+
+publishing {
+    publications {
+        main(MavenPublication) {
+            from components.java
+        }
+    }
+    repositories {
+        maven { setUrl("${rootProject.buildDir}/repo") }
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/differentClassloaders/js-app/src/main/kotlin/A.kt

@@ -0,0 +1,5 @@
+import com.example.mpp.lib.*
+
+fun main() {
+    println(hello())
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/differentClassloaders/jvm-app/build.gradle

@@ -0,0 +1,41 @@
+plugins {
+    id "org.jetbrains.kotlin.jvm"
+    id "maven-publish"
+    id "org.jetbrains.kotlin.plugin.allopen"
+}
+
+group = "com.example"
+version = "1.0"
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib"
+}
+
+if (project.findProperty("mppProjectDependency") == "true") {
+
+    dependencies {
+        api project(":mpp-lib")
+    }
+
+} else {
+
+    repositories {
+        maven { setUrl "${rootProject.buildDir}/repo" }
+    }
+
+    dependencies {
+        api "com.example:mpp-lib:1.0"
+    }
+
+}
+
+publishing {
+    publications {
+        main(MavenPublication) {
+            from components.java
+        }
+    }
+    repositories {
+        maven { setUrl("${rootProject.buildDir}/repo") }
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/differentClassloaders/jvm-app/src/main/kotlin/A.kt

@@ -0,0 +1,5 @@
+import com.example.mpp.lib.*
+
+fun main() {
+    println(hello())
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/differentClassloaders/mpp-lib/build.gradle

@@ -0,0 +1,42 @@
+plugins {
+    id "org.jetbrains.kotlin.multiplatform"
+    id "maven-publish"
+}
+
+group = "com.example"
+version = "1.0"
+
+kotlin {
+    jvm()
+    js()
+
+    sourceSets {
+        commonMain {
+            dependencies {
+                implementation 'org.jetbrains.kotlin:kotlin-stdlib-common'
+            }
+        }
+        jvmMain {
+            dependencies {
+                implementation 'org.jetbrains.kotlin:kotlin-stdlib'
+            }
+        }
+        jsMain {
+            dependencies {
+                implementation 'org.jetbrains.kotlin:kotlin-stdlib-js'
+            }
+        }
+    }
+}
+
+publishing {
+    publications {
+        jvm {
+            artifactId = "mpp-lib-myjvm"
+        }
+    }
+
+    repositories {
+        maven { setUrl("${rootProject.buildDir}/repo") }
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/differentClassloaders/mpp-lib/src/commonMain/kotlin/Hello.kt

@@ -0,0 +1,3 @@
+package com.example.mpp.lib
+
+fun hello(): String = "hello"

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/differentClassloaders/settings.gradle

@@ -0,0 +1 @@
+include(":mpp-lib", ":jvm-app", ":js-app")