Minor: replace UsefulTestCase with KtUsefulTestCase

UsefulTestCase does not resolve in IDE for some reason

compiler/incremental-compilation-impl/test/org/jetbrains/kotlin/incremental/AbstractIncrementalCompilerRunnerTestBase.kt

@@ -16,12 +16,12 @@
 
 package org.jetbrains.kotlin.incremental
 
-import com.intellij.testFramework.UsefulTestCase
 import org.jetbrains.kotlin.TestWithWorkingDir
 import org.jetbrains.kotlin.cli.common.ExitCode
 import org.jetbrains.kotlin.cli.common.arguments.CommonCompilerArguments
 import org.jetbrains.kotlin.incremental.testingUtils.*
 import org.jetbrains.kotlin.incremental.utils.TestCompilationResult
+import org.jetbrains.kotlin.test.testFramework.KtUsefulTestCase
 import org.junit.Assert
 import java.io.File
 
@@ -93,7 +93,7 @@ abstract class AbstractIncrementalCompilerRunnerTestBase<Args : CommonCompilerAr
                 // JPS logs should be updated carefully, because standalone logs are a bit different (no removed classes, iterations, etc)
                 Assert.assertEquals(expectedSB.toString(), actualSB.toString())
             } else {
-                UsefulTestCase.assertSameLinesWithFile(buildLogFile.canonicalPath, actualSB.toString(), false)
+                KtUsefulTestCase.assertSameLinesWithFile(buildLogFile.canonicalPath, actualSB.toString(), false)
             }
         }
 
@@ -155,7 +155,7 @@ abstract class AbstractIncrementalCompilerRunnerTestBase<Args : CommonCompilerAr
 
         @JvmStatic
         protected val kotlinStdlibJvm: File = File(distKotlincLib, "kotlin-stdlib.jar").also {
-            UsefulTestCase.assertExists(it)
+            KtUsefulTestCase.assertExists(it)
         }
     }
 }