OS_ShellOutputToFile_Impl in VxWorks is not thread safe

[skliper]

Is your feature request related to a problem? Please describe.
Filename is common:

osal/src/os/vxworks/src/os-impl-shell.c

Line 96 in ead5723

} while (taskNameToId(shellName) != ((TASK_ID)ERROR));

Describe the solution you'd like
At minimum document. Consider refactor for shell safe implementation. Although current cFS concept is to use a single app and even this should be avoided when possible (direct shell use is discouraged in production ops).

Describe alternatives you've considered
Deprecate/remove.

Additional context
None

Requester Info
Jacob Hageman - NASA/GSFC, OSAL code review