Make Array.size() a function instead of a property

Also add a deprecated extension property to help migration. This is done to
unify getting size of arrays and collections

compiler/testData/codegen/boxWithStdlib/reified/spreads.kt

@@ -1,6 +1,6 @@
 import kotlin.test.assertEquals
 
-fun <T> foo(vararg a: T) = a.size
+fun <T> foo(vararg a: T) = a.size()
 
 inline fun <reified T> bar(a: Array<T>, block: () -> T): Array<T> {
     assertEquals(4, foo(*a, block(), block()))