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/ranges/CoercionTest.kt

@@ -1,6 +1,5 @@
 package test.ranges
 
-import org.junit.Test
 import kotlin.test.*
 
 class CoercionTest {

libraries/stdlib/test/ranges/ProgressionLastElementTest.kt

@@ -1,8 +1,7 @@
 package test.ranges
 
-import org.junit.Test
 import kotlin.comparisons.*
-import kotlin.test.assertEquals
+import kotlin.test.*
 
 
 class ProgressionLastElementTest  {

libraries/stdlib/test/ranges/RangeIterationJVMTest.kt

@@ -11,7 +11,6 @@ import java.lang.Long.MAX_VALUE as MaxL
 import java.lang.Long.MIN_VALUE as MinL
 import java.lang.Character.MAX_VALUE as MaxC
 import java.lang.Character.MIN_VALUE as MinC
-import org.junit.Test
 import kotlin.test.*
 
 // Test data for codegen is generated from this class. If you change it, rerun GenerateTests

libraries/stdlib/test/ranges/RangeIterationTest.kt

@@ -1,6 +1,5 @@
 package test.ranges
 
-import org.junit.Test
 import test.collections.behaviors.iteratorBehavior
 import test.collections.compare
 import kotlin.test.*

libraries/stdlib/test/ranges/RangeTest.kt

@@ -1,7 +1,6 @@
 package test.ranges
 
 import kotlin.test.*
-import org.junit.Test
 
 public class RangeTest {
     @Test fun intRange() {