Unparallelize IO heavy tests

Alternative to GH-10892. This is somewhat unfortunate since these are also the
slow tests. I'm also not sure if this actually helps.

Closes GH-10953

Fix test in case fallocate(1) is available, but fails

That happens on Travis s390x for whatever reasons. Thus, instead of
checking for `fallocate -h`, we attempt the real allocation and

Fix test in case fallocate(1) is available, but fails

That happens on Travis s390x for whatever reasons. Thus, instead of
checking for `fallocate -h`, we attempt the real allocation and skip if
that fails.

show more ...

Fix #81145: copy() and stream_copy_to_stream() fail for +4GB files

When mapping the file, we need to pass the proper `dwFileOffsetHigh`
instead of `0`.

Co-authored-by: Nikita Po

Fix #81145: copy() and stream_copy_to_stream() fail for +4GB files

When mapping the file, we need to pass the proper `dwFileOffsetHigh`
instead of `0`.

Co-authored-by: Nikita Popov <nikita.ppv@gmail.com>

Closes GH-7158.

show more ...