Validate even more dictionary properties

This checks primarily Arrays, but also some other properties, that we'll end up sending (sometimes indirectly) to the main-thread.

src/core/core_utils.js

@@ -218,6 +218,21 @@ function isWhiteSpace(ch) {
   return ch === 0x20 || ch === 0x09 || ch === 0x0d || ch === 0x0a;
 }
 
+/**
+ * Checks if something is an Array containing only boolean values,
+ * and (optionally) checks its length.
+ * @param {any} arr
+ * @param {number | null} len
+ * @returns {boolean}
+ */
+function isBooleanArray(arr, len) {
+  return (
+    Array.isArray(arr) &&
+    (len === null || arr.length === len) &&
+    arr.every(x => typeof x === "boolean")
+  );
+}
+
 /**
  * Checks if something is an Array containing only numbers,
  * and (optionally) checks its length.
@@ -652,6 +667,7 @@ export {
   getRotationMatrix,
   getSizeInBytes,
   isAscii,
+  isBooleanArray,
   isNumberArray,
   isWhiteSpace,
   log2,