Clean up EBML size constants

Instead of using an array of Uint8Arrays, which could trigger a
load-time failure on very old browsers, store an array of number
arrays.  This is equivalent for the purpose of comparison, and it
cannot fail at load-time.

This cleanup seems to fix minor test flake in the EBML parser tests
that was observed with upgraded node modules.

Issue #1694

Change-Id: I87b2307bceddb3a21dfc81d4fe9828afd9508617

lib/util/uint8array_utils.js

@@ -109,8 +109,11 @@ shaka.util.Uint8ArrayUtils.toHex = function(arr) {
 
 /**
  * Compare two Uint8Arrays for equality.
- * @param {Uint8Array} arr1
- * @param {Uint8Array} arr2
+ * For convenience, this also accepts Arrays, so that one can trivially compare
+ * a Uint8Array to an Array of numbers.
+ *
+ * @param {(Uint8Array|Array.<number>)} arr1
+ * @param {(Uint8Array|Array.<number>)} arr2
  * @return {boolean}
  * @export
  */