linux: update ptrace_syscall_info struct

[Marcondiro]

Hi,

Description

linux: update ptrace_syscall_info struct:

• Add new flags field and reserveds.
• Rename wrongly named field sval to rval.

This is a breaking change and should probably not be backported to 0.2 considering also that at the time of writing the new fields are just for future usage.
The updated version has a different size on 32 bits arches (84 -> 88 bytes) while the size stays the same on 64 bits.

Sources

ptrace.h
kernel lore

Checklist

• Relevant tests in libc-test/semver have been updated
• No placeholder or unstable values like *LAST or *MAX are
  included (see #3131)
• Tested locally (cd libc-test && cargo test --target mytarget);
  especially relevant for platforms that may not be checked in CI

[rustbot]

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.