Remove run-pass/vec-alloc-append.rs

There is no ivec::append and this is the only remaining user of vec::append

src/test/run-pass/vec-alloc-append.rs

@@ -1,13 +0,0 @@
-
-
-// This is a test for issue #109.
-use std;
-
-fn slice[T](e: vec[T]) {
-    let result: vec[T] = std::vec::alloc[T](1 as uint);
-    log "alloced";
-    result += e;
-    log "appended";
-}
-
-fn main() { slice[str](["a"]); }