Fix encoding in |fs.readFileSync| calls ("utf-8" -> "utf8")

benchmark/run

@@ -105,7 +105,7 @@ sys.puts("");
 
 Runner.run(benchmarks, runCount, {
   readFile: function(file) {
-    return fs.readFileSync(file, "utf-8");
+    return fs.readFileSync(file, "utf8");
   },
 
   testStart: function(benchmark, test) {

test/run

@@ -81,7 +81,7 @@ QUnit.done = function(details) {
   "passes-test.js",
   "compiler-test.js",
 ].forEach(function(file) {
-  eval("with (QUnit) {" + fs.readFileSync(file, "utf-8") + "}");
+  eval("with (QUnit) {" + fs.readFileSync(file, "utf8") + "}");
 });
 
 QUnit.start();