tests: libc: Update character output testcases to solve coverity issues

1. Refine some testcases for testing some character output function.
2. Delete some negative testcases which will not invoke fatal error.

Fixes #33822
Fixes #33803
Fixes #33801
Fixes #33800
Fixes #33790

Signed-off-by: Ying ming <mingx.ying@intel.com>
1 file changed