[Test] Set static field with application to null after tests are completed

compiler/tests-common-new/tests/org/jetbrains/kotlin/test/ApplicationEnvironmentDisposer.kt

@@ -6,10 +6,12 @@
 package org.jetbrains.kotlin.test
 
 import com.intellij.openapi.Disposable
+import com.intellij.openapi.application.ApplicationManager
 import com.intellij.openapi.util.Disposer
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
 import org.junit.platform.launcher.TestExecutionListener
 import org.junit.platform.launcher.TestPlan
+import java.lang.reflect.Field
 
 class ApplicationEnvironmentDisposer : TestExecutionListener {
     companion object {
@@ -19,5 +21,8 @@ class ApplicationEnvironmentDisposer : TestExecutionListener {
     override fun testPlanExecutionFinished(testPlan: TestPlan) {
         KotlinCoreEnvironment.disposeApplicationEnvironment()
         Disposer.dispose(ROOT_DISPOSABLE)
+        val ourApplicationField: Field = ApplicationManager::class.java.getDeclaredField("ourApplication")
+        ourApplicationField.isAccessible = true
+        ourApplicationField.set(null, null)
     }
 }