Fuzzing has turned up that module linking can create large amounts of
tables and memories in addition to instances. For example if N instances
are allowed and M tables are allowed per-instance, then currently
wasmtime allows MxN tables (which is quite a lot). This is causing some
wasm-smith-generated modules to exceed resource limits while fuzzing!
This commits adds corresponding `max_tables` and `max_memories`
functions to sit alongside the `max_instances` configuration.
Additionally fuzzing now by default configures all of these to a
somewhat low value to avoid too much resource usage while fuzzing.
dccaa64962