Convert some comm tests to istrs. Issue #855

These spawn thunks need to take move-mode strings to be correct

src/test/run-pass/child-outlives-parent.rs

@@ -3,6 +3,6 @@
 use std;
 import std::task;
 
-fn child2(s: str) { }
+fn child2(s: -istr) { }
 
-fn main() { let x = task::spawn(bind child2("hi")); }
+fn main() { let x = task::spawn(bind child2(~"hi")); }

src/test/run-pass/spawn-fn.rs

@@ -4,12 +4,12 @@ use std;
 import std::task::yield;
 import std::task;
 
-fn x(s: str, n: int) { log s; log n; }
+fn x(s: -istr, n: int) { log s; log n; }
 
 fn main() {
-    task::spawn(bind x("hello from first spawned fn", 65));
-    task::spawn(bind x("hello from second spawned fn", 66));
-    task::spawn(bind x("hello from third spawned fn", 67));
+    task::spawn(bind x(~"hello from first spawned fn", 65));
+    task::spawn(bind x(~"hello from second spawned fn", 66));
+    task::spawn(bind x(~"hello from third spawned fn", 67));
     let i: int = 30;
     while i > 0 { i = i - 1; log "parent sleeping"; yield(); }
 }

src/test/run-pass/task-life-0.rs

@@ -1,7 +1,7 @@
 use std;
 import std::task;
-fn main() { task::spawn(bind child("Hello")); }
+fn main() { task::spawn(bind child(~"Hello")); }
 
-fn child(s: str) {
+fn child(s: -str) {
 
 }