* Limit the size of functions in the `stacks` fuzzer
The fuzzers recently found a timeout in this fuzz test case related to
the compile time of the generated module. Inspecting the generated
module showed that it had 100k+ opcodes for one function, so this commit
updates the fuzzer to limit the number of operations per-function to a
smaller amount to avoid timeout limits.
* Use `arbitrary_len` for `ops` length
* Fix a max/min flip
2696462ccb