Reimplement isEqual without pulling in massive lodash.isequal.

Follow-up to #4915. I have kept the tests from that PR, just not the
lodash-based implementation of isEqual.

The lodash.isequal package has a ton of extra features we don't need, and
weighs in at a whopping 10KB minified (3.8KB after gzip). Very little of
that machinery is really necessary to fix #4824.

I extracted this functionality into a separate npm package called
@wry/equality, so that we have the flexibility to depend on the same logic
in other packages without importing apollo-utilities.

packages/apollo-utilities/package.json

@@ -39,12 +39,9 @@
     "graphql": "^0.11.0 || ^0.12.0 || ^0.13.0 || ^14.0.0"
   },
   "dependencies": {
+    "@wry/equality": "^0.1.0",
     "fast-json-stable-stringify": "^2.0.0",
-    "lodash.isequal": "^4.5.0",
     "ts-invariant": "^0.4.0",
     "tslib": "^1.9.3"
-  },
-  "devDependencies": {
-    "@types/lodash.isequal": "^4.5.5"
   }
 }

packages/apollo-utilities/src/util/isEqual.ts

@@ -1,8 +1 @@
-import isEqualLodash from 'lodash.isequal';
-
-/**
- * Performs a deep equality check on two JavaScript values.
- */
-export function isEqual(a: any, b: any): boolean {
-  return isEqualLodash(a, b);
-}
+export { equal as isEqual } from '@wry/equality';