Multiplatform test annotations

Actual annotations are provided in kotlin-test-junit on JVM side
and in kotlin-test-js on JS side.

#KT-19696

libraries/kotlin.test/jvm/src/test/kotlin/BasicAssertionsJVMTest.kt

@@ -1,7 +1,6 @@
 package kotlin.test.tests
 
 import kotlin.test.*
-import org.junit.*
 
 class BasicAssertionsJVMTest {
 

libraries/kotlin.test/jvm/src/test/kotlin/CollectionAssertionTest.kt

@@ -1,7 +1,7 @@
 @file:Suppress("DEPRECATION")
 package kotlin.test.tests
 
-import org.junit.*
+import org.junit.Assert
 import java.util.*
 import kotlin.test.*
 

libraries/kotlin.test/jvm/src/test/kotlin/TestJVMTest.kt

@@ -17,7 +17,6 @@
 package kotlin.test.tests
 
 import kotlin.test.*
-import org.junit.Test
 
 class TestJVMTest {