Rename PropertyResolverExtensionsTests to Kotlin*

spring-core/src/test/kotlin/org/springframework/core/env/KotlinPropertyResolverExtensionsTests.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,7 +26,7 @@ import org.junit.jupiter.api.Test
  *
  * @author Sebastien Deleuze
  */
-class PropertyResolverExtensionsTests {
+class KotlinPropertyResolverExtensionsTests {
 
 	val propertyResolver = mockk<PropertyResolver>()