drop deprecated @platformName and @platformStatic annotations

compiler/testData/codegen/boxWithStdlib/fullJdk/native/default.kt

@@ -1,12 +1,11 @@
 package foo
 
 import kotlin.jvm.*
-import kotlin.platform.*
 
 object ObjWithNative {
     external fun foo(x: Int = 1): Double
 
-    @platformStatic external fun bar(l: Long, s: String = ""): Double
+    @JvmStatic external fun bar(l: Long, s: String = ""): Double
 }
 
 external fun topLevel(x: Int = 1): Double