Cleanup: fix some compiler warnings (mostly deprecations, javaClass)

core/util.runtime/src/org/jetbrains/kotlin/serialization/deserialization/BinaryVersion.kt

@@ -52,7 +52,8 @@ abstract class BinaryVersion(vararg val numbers: Int) {
     }
 
     override fun equals(other: Any?) =
-            this.javaClass == other?.javaClass &&
+            other != null &&
+            this::class.java == other::class.java &&
             major == (other as BinaryVersion).major && minor == other.minor && patch == other.patch && rest == other.rest
 
     override fun hashCode(): Int{

core/util.runtime/src/org/jetbrains/kotlin/utils/addToStdlib.kt

@@ -92,7 +92,7 @@ fun <T : Any> constant(calculator: () -> T): T {
     if (cached != null) return cached as T
 
     // safety check
-    val fields = calculator.javaClass.declaredFields.filter { it.modifiers.and(Modifier.STATIC) == 0 }
+    val fields = calculator::class.java.declaredFields.filter { it.modifiers.and(Modifier.STATIC) == 0 }
     assert(fields.isEmpty()) {
         "No fields in the passed lambda expected but ${fields.joinToString()} found"
     }

core/util.runtime/src/org/jetbrains/kotlin/utils/functions.kt

@@ -31,7 +31,7 @@ private val ALWAYS_NULL: (Any?) -> Any? = { null }
 fun <T, R: Any> alwaysNull(): (T) -> R? = ALWAYS_NULL as (T) -> R?
 
 val DO_NOTHING: (Any?) -> Unit = { }
-val DO_NOTHING_2: (Any?, Any?) -> Unit = { x, y -> }
-val DO_NOTHING_3: (Any?, Any?, Any?) -> Unit = { x, y, z -> }
+val DO_NOTHING_2: (Any?, Any?) -> Unit = { _, _ -> }
+val DO_NOTHING_3: (Any?, Any?, Any?) -> Unit = { _, _, _ -> }
 
 fun <T> doNothing(): (T) -> Unit = DO_NOTHING