Remove adhock flaky highlighting performance tests

We now have dedicated tests for it.

idea/tests/org/jetbrains/kotlin/idea/highlighter/HighlightingPerformanceTest.kt

@@ -1,54 +0,0 @@
-/*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package org.jetbrains.kotlin.idea.highlighter
-
-import com.intellij.psi.PsiManager
-import com.intellij.psi.impl.PsiModificationTrackerImpl
-import com.intellij.testFramework.LightProjectDescriptor
-import com.intellij.testFramework.PlatformTestUtil
-import org.jetbrains.kotlin.idea.test.KotlinLightCodeInsightFixtureTestCase
-import org.jetbrains.kotlin.idea.test.KotlinWithJdkAndRuntimeLightProjectDescriptor
-import org.jetbrains.kotlin.test.JUnit3WithIdeaConfigurationRunner
-import org.junit.runner.RunWith
-
-@RunWith(JUnit3WithIdeaConfigurationRunner::class)
-class HighlightingPerformanceTest : KotlinLightCodeInsightFixtureTestCase() {
-    private val text = """
-        fun test(a: String, b: ArrayList<java.util.Date>) {
-            println(a + b)
-        }
-    """.trimIndent()
-
-    fun testModificationCountInc() {
-        myFixture.configureByText("temp.kt", text)
-        highlight()
-
-        val tracker = PsiManager.getInstance(myFixture.project).modificationTracker as PsiModificationTrackerImpl
-
-        PlatformTestUtil.assertTiming("Update local cache", 100) { // actual timing is ~55
-            tracker.modificationCount.inc()
-            highlight()
-        }
-    }
-
-    fun testOutOfBlockModificationCountInc() {
-        myFixture.configureByText("temp.kt", text)
-        highlight()
-
-        val tracker = PsiManager.getInstance(myFixture.project).modificationTracker as PsiModificationTrackerImpl
-
-        PlatformTestUtil.assertTiming("Update all trackers", 200) { // actual timing is ~165
-            tracker.incOutOfCodeBlockModificationCounter()
-            highlight()
-        }
-    }
-
-    override fun getProjectDescriptor(): LightProjectDescriptor = KotlinWithJdkAndRuntimeLightProjectDescriptor.INSTANCE_FULL_JDK
-
-    private fun highlight() {
-        myFixture.checkHighlighting(true, false, true)
-    }
-}