Add Gradle task to clean test kit cache dir.

Always run it on CI when tests will finish.
^KT-45744 In Progress

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

@@ -61,6 +61,14 @@ val isTeamcityBuild = project.kotlinBuildProperties.isTeamcityBuild ||
                 ?.toBoolean() ?: false
         } catch (_: Exception) { false }
 
+
+val cleanTestKitCacheTask = tasks.register<Delete>("cleanTestKitCache") {
+    group = "Build"
+    description = "Deletes temporary Gradle TestKit cache"
+
+    delete(project.file(".testKitDir"))
+}
+
 fun Test.includeMppAndAndroid(include: Boolean) {
     if (isTeamcityBuild) {
         val mppAndAndroidTestPatterns = listOf("*Multiplatform*", "*Mpp*", "*Android*")
@@ -95,6 +103,7 @@ projectTest(
 ) {
     includeMppAndAndroid(false)
     includeNative(false)
+    if (isTeamcityBuild) finalizedBy(cleanTestKitCacheTask)
 }
 
 projectTest(
@@ -105,6 +114,8 @@ projectTest(
     advanceGradleVersion()
     includeMppAndAndroid(false)
     includeNative(false)
+
+    if (isTeamcityBuild) finalizedBy(cleanTestKitCacheTask)
 }
 
 if (isTeamcityBuild) {
@@ -114,6 +125,7 @@ if (isTeamcityBuild) {
         jUnit5Enabled = true
     ) {
         includeNative(true)
+        finalizedBy(cleanTestKitCacheTask)
     }
 
     projectTest(
@@ -123,6 +135,7 @@ if (isTeamcityBuild) {
     ) {
         advanceGradleVersion()
         includeNative(true)
+        finalizedBy(cleanTestKitCacheTask)
     }
 
     projectTest(
@@ -131,6 +144,7 @@ if (isTeamcityBuild) {
         jUnit5Enabled = true
     ) {
         includeMppAndAndroid(true)
+        finalizedBy(cleanTestKitCacheTask)
     }
 
     projectTest(
@@ -140,6 +154,7 @@ if (isTeamcityBuild) {
     ) {
         advanceGradleVersion()
         includeMppAndAndroid(true)
+        finalizedBy(cleanTestKitCacheTask)
     }
 }
 
@@ -150,6 +165,7 @@ tasks.named<Task>("check") {
         dependsOn("testMppAndAndroid")
         dependsOn("testNative")
         dependsOn("testAdvanceGradleVersionNative")
+        finalizedBy(cleanTestKitCacheTask)
     }
 }
 

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

@@ -38,7 +38,7 @@ fun KGPBaseTest.project(
     val gradleRunner = GradleRunner
         .create()
         .withProjectDir(projectPath.toFile())
-        .withTestKitDir(Paths.get(".").testKitDir.toAbsolutePath().toFile())
+        .withTestKitDir(testKitDir.toAbsolutePath().toFile())
         .withGradleVersion(gradleVersion.version)
         .also {
             if (forceOutput) it.forwardOutput()
@@ -105,7 +105,10 @@ private fun TestProject.commonBuildSetup(
     return allBuildArguments
 }
 
-private val Path.testKitDir get() = resolve(".testKitDir")
+/**
+ * On changing test kit dir location update related location in 'cleanTestKitCache' task.
+ */
+private val testKitDir get() = Paths.get(".").resolve(".testKitDir")
 
 private fun setupProjectFromTestResources(
     projectName: String,