Remove rm() as a duplicate of unlink(), but adopt its code into unlink()

src/core/IO.pm

@@ -226,23 +226,10 @@ sub slurp($filename) {
 }
 
 sub unlink($filename) {
-    Q:PIR {
-        .local string filename_str
-        .local pmc filename_pmc, os
-        .local int status
-        filename_pmc = find_lex '$filename'
-        filename_str = filename_pmc
-        os = root_new ['parrot';'OS']
-        push_eh unlink_catch
-        os.'rm'(filename_str)
-        status = 1
-        goto unlink_finally
-      unlink_catch:
-        status = 0
-      unlink_finally:
-        pop_eh
-        %r = box status
+    try {
+        pir::new__PS('OS').rm($path);
     }
+    $! ?? fail($!) !! True
 }
 
 # CHEAT: This function is missing a bunch of arguments,
@@ -313,13 +300,6 @@ multi sub copy($src as Str, $dest as Str) {
     $! ?? fail($!) !! True
 }
 
-multi sub rm($path as Str) {
-    try { 
-        pir::new__PS('OS').rm($path);
-    }
-    $! ?? fail($!) !! True
-}
-
 multi sub link($src as Str, $dest as Str, Bool :$hard = False) {
     if $hard {
         try {