Move IsLittleEndianCached and IsEvalSupportedCached to src/shared/util.js

Rather than duplicating the lookup and caching in multiple files, it seems easier to simply move all of this functionality into `src/shared/util.js` instead.
This will also help avoid a bunch of ESLint errors once the `no-shadow` rule is eventually enabled.

src/display/canvas.js

@@ -18,7 +18,7 @@ import {
   IDENTITY_MATRIX,
   ImageKind,
   info,
-  isLittleEndian,
+  IsLittleEndianCached,
   isNum,
   OPS,
   shadow,
@@ -46,12 +46,6 @@ var MAX_SIZE_TO_COMPILE = 1000;
 
 var FULL_CHUNK_HEIGHT = 16;
 
-var IsLittleEndianCached = {
-  get value() {
-    return shadow(IsLittleEndianCached, "value", isLittleEndian());
-  },
-};
-
 function addContextCurrentTransform(ctx) {
   // If the context doesn't expose a `mozCurrentTransform`, add a JS based one.
   if (!ctx.mozCurrentTransform) {