perf: add isSimpleValidator

[Uzlopak]

This PR adds a helper method called isSimpleValidator. Basically it is a function to determine if a validator is just a simple object or if it is a more complex one. To avoid the usage in other places, it is not named isFlatObject. It uses a WeakMap to cache the result and gain as such speed.

With isSimpleValidator we determine if we should make a deep clone of the validator or a shallow copy of it with Object.assign.

Before:

MONGOOSE_DEV=1 node validate
invalid x 23,461 ops/sec ±0.78% (89 runs sampled)
valid x 75,657 ops/sec ±0.67% (90 runs sampled)

after

MONGOOSE_DEV=1 node validate
invalid x 29,047 ops/sec ±0.37% (95 runs sampled)
valid x 148,950 ops/sec ±0.29% (93 runs sampled)

So we basically double the performance on the valid path.

[Uzlopak]

If we combine this with #11408 we get super performance speed for validation :D

[Uzlopak]

With the improved benchmark from #11415
before:

before:

MONGOOSE_DEV=1 node validate
invalid async x 21,179 ops/sec ±0.71% (84 runs sampled)
valid async x 41,408 ops/sec ±1.34% (83 runs sampled)
invalid sync x 24,553 ops/sec ±0.76% (93 runs sampled)
valid sync x 76,212 ops/sec ±0.67% (92 runs sampled)

after:

 MONGOOSE_DEV=1 node validate
invalid async x 23,496 ops/sec ±1.08% (82 runs sampled)
valid async x 60,767 ops/sec ±1.08% (80 runs sampled)
invalid sync x 27,526 ops/sec ±1.27% (92 runs sampled)
valid sync x 142,613 ops/sec ±0.36% (96 runs sampled)

[AbdelrahmanHafez]

LGTM 👍

[vkarpov15]

My only request would be to get rid of the caching. I know that it should be faster and the risk of WeakMap() causing any sort of memory issue is extremely low, but I'd rather write off that risk altogether and just keep this as a simple loop.

[vkarpov15]

I'll merge this and remove the WeakMap caching locally

[Uzlopak]

Seems like the performance is still very good. Strange. Expected a higher performance penalty. But hey, i dont complain.