Refactor to avoid dynamic module resolution

Author: kgryte

lib/node_modules/@stdlib/buffer/from-string/lib/index.js

@@ -15,15 +15,17 @@
 // MODULES //
 
 var hasFrom = require( './has_from.js' );
+var main = require( './main.js' );
+var polyfill = require( './polyfill.js' );
 
 
 // MAIN //
 
 var string2buffer;
 if ( hasFrom ) {
-	string2buffer = require( './main.js' );
+	string2buffer = main;
 } else {
-	string2buffer = require( './polyfill.js' );
+	string2buffer = polyfill;
 }