Use kotlin.test.Test instead of org.junit.Test in common stdlib tests

(and in jvm-only and js-only tests also)

libraries/stdlib/test/utils/KotlinVersionTest.kt

@@ -1,6 +1,5 @@
 package test.utils
 
-import org.junit.Test
 import kotlin.test.*
 
 

libraries/stdlib/test/utils/LazyJVMTest.kt

@@ -8,7 +8,6 @@ import java.io.*
 import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.atomic.AtomicInteger
 import kotlin.concurrent.thread
-import org.junit.Test
 import test.io.serializeAndDeserialize
 
 class LazyJVMTest {

libraries/stdlib/test/utils/LazyTest.kt

@@ -2,7 +2,6 @@ package test.utils
 
 import kotlin.*
 import kotlin.test.*
-import org.junit.Test
 
 class LazyTest {
 

libraries/stdlib/test/utils/PreconditionsTest.kt

@@ -1,6 +1,5 @@
 package test.utils
 
-import org.junit.Test
 import kotlin.test.*
 
 class PreconditionsTest() {

libraries/stdlib/test/utils/TODOTest.kt

@@ -18,7 +18,6 @@ package test.utils
 
 import kotlin.*
 import kotlin.test.*
-import org.junit.Test
 
 class TODOTest {
     private class PartiallyImplementedClass {