Remove *ImplTest for Kotlin Gradle Models

Equality should already be guaranteed by Kotlin data classes.

libraries/tools/kotlin-allopen/src/test/kotlin/org/jetbrains/kotlin/allopen/gradle/model/impl/AllOpenImplTest.kt

@@ -1,19 +0,0 @@
-/*
- * Copyright 2010-2018 JetBrains s.r.o. 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.allopen.gradle.model.impl
-
-
-import nl.jqno.equalsverifier.EqualsVerifier
-import nl.jqno.equalsverifier.Warning
-import org.junit.Test
-
-class AllOpenImplTest {
-    @Test
-    @Throws(Exception::class)
-    fun equals() {
-        EqualsVerifier.forClass(AllOpenImpl::class.java).suppress(Warning.NULL_FIELDS).verify()
-    }
-}