fix: Forbid usage of instanceof ArrayBuffer (#7653)

Fixes #6279

lib/util/uint8array_utils.js

@@ -119,8 +119,9 @@ shaka.util.Uint8ArrayUtils = class {
 
     for (let i = 0; i < varArgs.length; ++i) {
       const value = varArgs[i];
-      if (value instanceof Uint8Array) {
-        result.set(value, offset);
+      if (ArrayBuffer.isView(value) &&
+      /** @type {TypedArray} */ (value).BYTES_PER_ELEMENT === 1) {
+        result.set(/** @type {!Uint8Array} */(value), offset);
       } else {
         result.set(BufferUtils.toUint8(value), offset);
       }