Replace get() and set() to getValue() and setValue() (property delegates)

compiler/testData/diagnostics/tests/inference/regressions/kt3496.kt

@@ -5,5 +5,5 @@ class B<T> {
     fun <S> x (y: B<Iterable<S>>) {
         val z: S = y[""] // does not work with [], but works with .get()
     }
-    operator fun <S> get(s : String): S = throw Exception()
+    operator fun <S> get(<!UNUSED_PARAMETER!>s<!> : String): S = throw Exception()
 }

compiler/testData/diagnostics/tests/inference/regressions/kt3496_2.kt

@@ -8,4 +8,4 @@ class F<T> {
         val z: ArrayList<T> = y["", w]
     }
 }
-operator fun <V, T> Any.get(s: String, w: ArrayList<V>): ArrayList<T> = throw Exception()
+operator fun <V, T> Any.get(<!UNUSED_PARAMETER!>s<!>: String, <!UNUSED_PARAMETER!>w<!>: ArrayList<V>): ArrayList<T> = throw Exception()