Uninitialized variables in UT, potential test failure

[skliper]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I reviewed the README file to see if the feature is in the major future work.
• I performed a cursory search to see if the feature request is relevant, not redundant, nor in conflict with other tickets.

Is your feature request related to a problem? Please describe.
The destination file table and filter table are not consistently initialized in unit tests. Example where DestFileTable isn't fully initialized:

DS/unit-test/ds_file_tests.c

Lines 729 to 740 in 9d0651c

	void DS_FileCreateDest_Test_StringTerminate(void)
	{
	uint32 FileIndex = 0;
	DS_DestFileTable_t DestFileTable;
	/* Setup for DS_FileCreateName to succeed */
	DS_AppData.DestFileTblPtr = &DestFileTable;
	DS_AppData.FileStatus[FileIndex].FileName[0] = DS_STRING_TERMINATOR;
	/* Execute the function being tested */
	UtAssert_VOIDCALL(DS_FileCreateDest(FileIndex));

Observed test failure:

[BEGIN] 16 DS_FileCreateDest_Test_StringTerminate
[ PASS] 16.001 ds_file_tests.c:740 - DS_FileCreateDest(FileIndex)
[ FAIL] 16.002 ds_file_tests.c:743 - CallCount OS_OpenCreate() (1) == 0 (0)
[  END] 16 DS_FileCreateDest_Test_StringTerminate TOTAL::2     PASS::1     FAIL::1     MIR::0     TSF::0     TTF::0     WARN::0

Assuming there's a combination of random file name components that pass, which then cause OS_OpenCreate to be called.

Describe the solution you'd like
Implement a consistent initialization scheme for commonly used elements

Describe alternatives you've considered
None

Additional context
None

Requester Info
Jacob Hageman - NASA/GSFC