tests: posix: common: split XSI_REALTIME to standalone test

[Pancakem]

Fixes #83634

posix.common contains testsuites that can be separated into smaller groups of tests.

This change moves XSI_REALTIME tests into a singular testsuite at tests/posix/xsi_realtime app directory.

[cfriedt]

This is a tricky one.

_POSIX_MESSAGE_PASSING is an Option and not an Option Group.

At some point, it would be nice if the standards body made it a proper Option Group.

Maybe it's best to keep it in common for now? What do you think @ycsin ?

[cfriedt]

Aha - found it here.

The Realtime Option Group is denoted by the symbolic constant _XOPEN_REALTIME.
...
If the symbolic constant _XOPEN_REALTIME is defined to have a value other than -1, then the following symbolic constants shall be defined by the implementation to have the value 200809L:

_POSIX_FSYNC
_POSIX_MEMLOCK
_POSIX_MEMLOCK_RANGE
_POSIX_MESSAGE_PASSING
_POSIX_PRIORITY_SCHEDULING
_POSIX_SHARED_MEMORY_OBJECTS
_POSIX_SYNCHRONIZED_IO

Aside from _POSIX_SHARED_MEMORY_OBJECTS implying the existence of shm_open() and shm_unlink() (mmap(), and munmap() are already covered by POSIX_MAPPED_FILES)

Most of these options (including _POSIX_FSYNC), are not owned by a proper POSIX or XSI Option Group.

So I woulud say that we need to define at least one additional Option Group.

Based on existing naming conventions, for the _XOPEN_REALTIME Option, there should be a corresponding XSI_REALTIME Option Group. A few of these XSI Option Groups have a mention in the spec, but no explicit definition in Subprofiling Considerations.

So @Pancakem - can you please

1. rename message_passing to xsi_realtime in this PR?
2. colocate the existing shm testsuite into the new xsi_realtime suite

There may be other existing tests that should be moved, but I have to get to some other things atm.

@ycsin - if you have time at some point, can you please create an issue to create the XSI_REALTIME option group? For that issue, we should look at folding Kconfig.sync_io, Kconfig.mqueue, and parts of Kconfig.mem into Kconfig.xsi_realtime?

[ycsin]

@ycsin - if you have time at some point, can you please create an issue to create the XSI_REALTIME option group?

#82004

[cfriedt]

We should wait to merge this until 82004 is done

[cfriedt]

@Pancakem - #83303 should add the missing option group, and then that will unblock you in this PR.

[cfriedt]

@Pancakem - can you please move tests related to the following, into a new xsi_realtime testsuite?

_POSIX_FSYNC
_POSIX_MEMLOCK
_POSIX_MEMLOCK_RANGE
_POSIX_MESSAGE_PASSING
_POSIX_PRIORITY_SCHEDULING
_POSIX_SHARED_MEMORY_OBJECTS
_POSIX_SYNCHRONIZED_IO

[Pancakem]

@Pancakem - can you please move tests related to the following, into a new xsi_realtime testsuite?

_POSIX_FSYNC
_POSIX_MEMLOCK
_POSIX_MEMLOCK_RANGE
_POSIX_MESSAGE_PASSING
_POSIX_PRIORITY_SCHEDULING
_POSIX_SHARED_MEMORY_OBJECTS
_POSIX_SYNCHRONIZED_IO

Alright on it.

[Pancakem]

@cfriedt should posix/fs also move into this since fsync and fdatasync are tested in it?

[cfriedt]

@cfriedt should posix/fs also move into this since fsync and fdatasync are tested in it?

@Pancakem - no, just move the fsync and fdatasync tests. We want to organize suites by Option Group, and POSIX_FILE_SYSTEM tests should remain here.

[cfriedt]

Preemptive +1

[ycsin]

LGTM