Make Comparator fun interface

Remove SAM-constructor-like function, it is no longer needed.

(cherry picked from commit d76e8f20752fdd75d1e7b0db05019c8516a74ba6)

runtime/src/main/kotlin/kotlin/Comparator.kt

@@ -5,12 +5,6 @@
 
 package kotlin
 
-actual public interface Comparator<T> {
+public actual fun interface Comparator<T> {
-    actual fun compare(a: T, b: T): Int
+    public actual fun compare(a: T, b: T): Int
 }
-
-actual public inline fun <T> Comparator(crossinline comparison: (a: T, b: T) -> Int): Comparator<T> {
-    return object: Comparator<T> {
-        override fun compare(a: T, b: T) = comparison(a, b)
-    }
-}