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/reflection/genericSignature/kt6106.kt

@@ -18,7 +18,7 @@ fun box(): String {
     val method = javaClass<A>().getDeclaredMethod("a", javaClass<B>())
     val genericParameterTypes = method.getGenericParameterTypes()
 
-    if (genericParameterTypes.size != 1) return "Wrong number of generic parameters"
+    if (genericParameterTypes.size() != 1) return "Wrong number of generic parameters"
 
     if (genericParameterTypes[0].toString() != "T") return "Wrong parameter type ${genericParameterTypes[0].toString()}"