Support custom accessors for top-level properties in scripts.

compiler/testData/codegen/box/intrinsics/prefixIncDec.kt

@@ -1,4 +1,4 @@
-public var inc: Int = 0;
+public var inc: Int = 0
 
 public var propInc: Int = 0
     get() {++inc; return field}
@@ -7,9 +7,9 @@ public var propInc: Int = 0
         field = a
     }
 
-public var dec: Int = 0;
+public var dec: Int = 0
 
-public var propDec: Int = 0;
+public var propDec: Int = 0
     get() { --dec; return field}
     set(a: Int) {
         --dec