Fuzzer: Ignore fuzz testcases that make VMs run out of stack (#6376)

When the stack runs out is observable and optimizations can change it, so
we must ignore such testcases.

Also add some logic to help debug stuff like this, as suggested by tlively
in the past, to add some metrics on the reasons we ignored a testcase. That
emits something like this:

(ignored 253 iters, for reasons {'too many errors vs calls': 230,
'[host limit ': 20, 'uninitialized non-defaultable local': 3})                                                              

As a drive by make the metrics print wasm bytes/iter rather than by second
(the former is easy to compute from the latter anyhow, and the latter is more
interesting I think).

0 files changed, 0 insertions, 0 deletions