ostest/hrtimer: Fix typos

[wangchdo]

Summary

The current code incorrectly used the CONFIG_SCHED_EVENTS
macro in ostest.h for hrtimer_test(). This has been corrected to use CONFIG_HRTIMER.

Impact

Fix typos for hrtimer api tests

Testing

ostest passed on rv-virt:smp64 with apache/nuttx#17573 applied and HRTIMER enabled.

NuttShell (NSH)
nsh> 
nsh> uname -a
NuttX 0.0.0 26f4bbc328-dirty Dec 25 2025 12:56:52 risc-v rv-virt
nsh> 
nsh> ostest

(...)

user_main: hrtimer test

End of test memory usage:
VARIABLE  BEFORE   AFTER
======== ======== ========
arena     1fbdea0  1fbdea0
ordblks        10       10
mxordblk  1f9a7d8  1f9a7d8
uordblks    14c68    16868
fordblks  1fa9238  1fa7638

Final memory usage:
VARIABLE  BEFORE   AFTER
======== ======== ========
arena     1fbdea0  1fbdea0
ordblks         1       10
mxordblk  1fb2cc0  1f9a7d8
uordblks     b1e0    16868
fordblks  1fb2cc0  1fa7638
user_main: Exiting
ostest_main: Exiting with status 0