Remove usage of ASCII encoding

Author: vmutafov

test-app/runtime/src/main/java/com/tns/Runtime.java

@@ -284,7 +284,7 @@ public static String getStackTraceErrorMessage(Throwable ex) {
             ex.printStackTrace(ps);
 
             try {
-                content = baos.toString("US-ASCII");
+                content = baos.toString("UTF-8");
                 if (ex instanceof NativeScriptException) {
                     content = getStackTraceOnly(content);
                     content = ((NativeScriptException) ex).getIncomingStackTrace() + content;