Mass rename uint/int to usize/isize

Now that support has been removed, all lingering use cases are renamed.

src/test/codegen/scalar-function-call.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-fn foo(x: int) -> int {
+fn foo(x: isize) -> isize {
     x * x
 }