Stop mangle common project descriptor in GenerateTestSupport tests

Use custom project descriptor instead.

Mitingate flaky failures:

ERROR: Save settings failed
java.lang.RuntimeException: java.io.IOException: Cannot save /test_path/test.ipr.
Unable to open the file for writing.
  at com.intellij.util.ExceptionUtil.rethrow(ExceptionUtil.java:116)
  at com.intellij.util.lang.CompoundRuntimeException.throwIfNotEmpty(CompoundRuntimeException.java:106)
  at com.intellij.configurationStore.SaveResult.throwIfErrored(SaveResult.kt:59)
  at com.intellij.configurationStore.ComponentStoreImpl.save$suspendImpl(ComponentStoreImpl.kt:152)
  at com.intellij.configurationStore.ComponentStoreImpl$save$1.invokeSuspend(ComponentStoreImpl.kt)
  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
  at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:56)
  at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:274)
  at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:84)
  at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:59)
  at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source)
  at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:38)
  at kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source)
  at com.intellij.configurationStore.StoreUtil$Companion.saveSettings(storeUtil.kt:44)
  at com.intellij.configurationStore.StoreUtil.saveSettings(storeUtil.kt)
  at com.intellij.openapi.project.impl.ProjectImpl.save(ProjectImpl.java:157)
  at org.jetbrains.kotlin.idea.codeInsight.generate.AbstractGenerateTestSupportMethodActionTest$setUpTestSourceRoot$1.invoke(AbstractGenerateTestSupportMethodActionTest.kt:22)
  at org.jetbrains.kotlin.idea.codeInsight.generate.AbstractGenerateTestSupportMethodActionTest$setUpTestSourceRoot$1.invoke(AbstractGenerateTestSupportMethodActionTest.kt:20)

idea/tests/org/jetbrains/kotlin/idea/codeInsight/generate/AbstractCodeInsightActionTest.kt

@@ -10,6 +10,7 @@ import com.intellij.openapi.actionSystem.AnAction
 import com.intellij.openapi.actionSystem.Presentation
 import com.intellij.openapi.util.io.FileUtil
 import com.intellij.refactoring.util.CommonRefactoringUtil
+import com.intellij.testFramework.LightProjectDescriptor
 import com.intellij.testFramework.PlatformTestUtil
 import com.intellij.testFramework.TestActionEvent
 import junit.framework.ComparisonFailure
@@ -113,5 +114,5 @@ abstract class AbstractCodeInsightActionTest : KotlinLightCodeInsightFixtureTest
         }
     }
 
-    override fun getProjectDescriptor() = KotlinWithJdkAndRuntimeLightProjectDescriptor.INSTANCE
+    override fun getProjectDescriptor(): LightProjectDescriptor = KotlinWithJdkAndRuntimeLightProjectDescriptor.INSTANCE
 }

idea/tests/org/jetbrains/kotlin/idea/codeInsight/generate/AbstractGenerateTestSupportMethodActionTest.kt

@@ -5,30 +5,27 @@
 
 package org.jetbrains.kotlin.idea.codeInsight.generate
 
-import com.intellij.openapi.roots.ModuleRootManager
+import com.intellij.openapi.module.ModuleTypeId
+import com.intellij.openapi.projectRoots.Sdk
+import com.intellij.testFramework.LightProjectDescriptor
+import org.jetbrains.jps.model.java.JavaSourceRootType
+import org.jetbrains.jps.model.module.JpsModuleSourceRootType
 import org.jetbrains.kotlin.idea.actions.generate.KotlinGenerateTestSupportActionBase
-import org.jetbrains.kotlin.idea.util.application.runWriteAction
+import org.jetbrains.kotlin.idea.test.PluginTestCaseBase
 import org.jetbrains.kotlin.test.InTextDirectivesUtils
 
 abstract class AbstractGenerateTestSupportMethodActionTest : AbstractCodeInsightActionTest() {
-    private fun setUpTestSourceRoot() {
-        val model = ModuleRootManager.getInstance(module).modifiableModel
-        val entry = model.contentEntries.single()
-        val sourceFolderFile = entry.sourceFolderFiles.single()
-        entry.removeSourceFolder(entry.sourceFolders.single())
-        entry.addSourceFolder(sourceFolderFile, true)
-        runWriteAction {
-            model.commit()
-            module.project.save()
-        }
-    }
-
     override fun createAction(fileText: String) = (super.createAction(fileText) as KotlinGenerateTestSupportActionBase).apply {
         testFrameworkToUse = InTextDirectivesUtils.findStringWithPrefixes(fileText, "// TEST_FRAMEWORK:")
     }
 
-    override fun doTest(path: String) {
-        setUpTestSourceRoot()
-        super.doTest(path)
+    override fun getProjectDescriptor(): LightProjectDescriptor = TEST_ROOT_PROJECT_DESCRIPTOR
+
+    companion object {
+        val TEST_ROOT_PROJECT_DESCRIPTOR = object : LightProjectDescriptor() {
+            override fun getModuleTypeId(): String = ModuleTypeId.JAVA_MODULE
+            override fun getSdk(): Sdk = PluginTestCaseBase.mockJdk()
+            override fun getSourceRootType(): JpsModuleSourceRootType<*> = JavaSourceRootType.TEST_SOURCE
+        }
     }
 }