Remove simplified geometry cache

[simonseyock]

Removed simplified geometry cache because it would bloat memory usage if used with non-integer zoom levels.

[tschaub]

Fixes #9977. Thanks @simonseyock.

For others following along, the geometry.simplify() method no longer returns a cached result. Within the library, we now call geometry.simplifyTransformed(), which is a memoized function - caching the result from a single call.