lib: refactor code with startsWith/endsWith

reduce using RegExp for string test. This pull reuqest replaces
various usages of regular expressions in favor of the ES2015
startsWith and endsWith methods.

PR-URL: https://github.com/nodejs/node/pull/5753


Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>