Fd validity and basic bound checks on fd_advise

[yagehu]

This commit fixes fd_advise unconditionally returning ok (0) on all inputs. The details are discussed in issue #4554.

Description

#4554 discusses the motivation. This is a behavior divergence between Wasmer and all other Wasm runtimes.

fixes #4554

[theduke]

@yagehu once again, many thanks!

I pushed a commit that adds a test validating the behaviour.

The invalid file descriptor error is as expected, but the overflow still returns a 0, could you check why?
(if not we will follow up)

To run the tests:

• compile the release binary
• cd tests/wasi-fyi; ./test.sh

[yagehu]

@theduke Thanks for demonstrating the fyi test! I was having a hard time finding the right test suite to add to.

Since filesize is spec'd as u64, I adjusted the extern "C" signature accordingly and now it indeed errors as expected. Previously, i64::MAX added to itself would not overflow an u64.