Add a getArrayLookupTableFactory helper function and use it to re-format src/core/{glyphlist, unicode}.js

*Please note:* Once https://bugzilla.mozilla.org/show_bug.cgi?id=1247687 is implemented, and we've removed SystemJS completely, this entire patch can (and even should) be reverted.

This is similar to the existing `getLookupTableFactory` helper function, but is implemented as outlined in issue 6774.
The re-formatting of the tables were done automatically, by using find-and-replace with regular expressions.

For reasons that I don't even pretend to understand, using this particular structure for these *very* long lookup tables allow SystemJS to process the files correctly/quickly and the development viewer thus works as intended.

src/core/core_utils.js

@@ -27,6 +27,22 @@ function getLookupTableFactory(initializer) {
   };
 }
 
+function getArrayLookupTableFactory(initializer) {
+  let lookup;
+  return function () {
+    if (initializer) {
+      let arr = initializer();
+      initializer = null;
+      lookup = Object.create(null);
+      for (let i = 0, ii = arr.length; i < ii; i += 2) {
+        lookup[arr[i]] = arr[i + 1];
+      }
+      arr = null;
+    }
+    return lookup;
+  };
+}
+
 class MissingDataException extends BaseException {
   constructor(begin, end) {
     super(`Missing data [${begin}, ${end})`);
@@ -212,6 +228,7 @@ function escapePDFName(str) {
 export {
   escapePDFName,
   getLookupTableFactory,
+  getArrayLookupTableFactory,
   MissingDataException,
   XRefEntryException,
   XRefParseException,