[Refactor] use has-symbols/shams and has-bigints to more robustly…

… detect these things

package.json

@@ -39,6 +39,8 @@
 		"es-get-iterator": "^1.1.2",
 		"functions-have-names": "^1.2.2",
 		"has": "^1.0.3",
+		"has-bigints": "^1.0.1",
+		"has-symbols": "^1.0.2",
 		"is-arrow-function": "^2.0.3",
 		"is-bigint": "^1.0.2",
 		"is-boolean-object": "^1.1.1",
@@ -65,8 +67,6 @@
 		"es6-shim": "^0.35.6",
 		"eslint": "^7.25.0",
 		"foreach": "^2.0.5",
-		"has-bigints": "^1.0.1",
-		"has-symbols": "^1.0.2",
 		"make-arrow-function": "~1.1.0",
 		"nyc": "^10.3.2",
 		"safe-publish-latest": "^1.1.4",

why.js

@@ -19,16 +19,18 @@ var getIterator = require('es-get-iterator');
 var whichCollection = require('which-collection');
 var whichBoxedPrimitive = require('which-boxed-primitive');
 var getPrototypeOf = require('object.getprototypeof/polyfill')();
+var hasSymbols = require('has-symbols/shams')();
+var hasBigInts = require('has-bigints')();
 
 var objectType = function (v) { return whichCollection(v) || whichBoxedPrimitive(v) || typeof v; };
 
 var isProto = Object.prototype.isPrototypeOf;
 
 var functionsHaveNames = require('functions-have-names')();
 
-var symbolValue = typeof Symbol === 'function' ? Symbol.prototype.valueOf : null;
+var symbolValue = hasSymbols ? Symbol.prototype.valueOf : null;
 
-var bigIntValue = typeof BigInt === 'function' ? BigInt.prototype.valueOf : null;
+var bigIntValue = hasBigInts ? BigInt.prototype.valueOf : null;
 
 var normalizeFnWhitespace = function normalizeWhitespace(fnStr) {
 	// this is needed in IE 9, at least, which has inconsistencies here.