Convert old-style for loops to new-style

Most could use the each method, but because of the hack used to
disambiguate old- and new-style loops, some had to use vec::each.

(This hack will go away soon.)

Issue #1619

src/compiletest/compiletest.rs

@@ -135,7 +135,7 @@ fn test_opts(config: config) -> test::test_opts {
 fn make_tests(config: config) -> [test::test_desc] {
     #debug("making tests from %s", config.src_base);
     let mut tests = [];
-    for file: str in os::list_dir_path(config.src_base) {
+    for os::list_dir_path(config.src_base).each {|file|
         let file = file;
         #debug("inspecting file %s", file);
         if is_test(config, file) {
@@ -154,11 +154,11 @@ fn is_test(config: config, testfile: str) -> bool {
 
     let mut valid = false;
 
-    for ext in valid_extensions {
+    for valid_extensions.each {|ext|
         if str::ends_with(name, ext) { valid = true; }
     }
 
-    for pre in invalid_prefixes {
+    for invalid_prefixes.each {|pre|
         if str::starts_with(name, pre) { valid = false; }
     }