selftests: tc-testing: Fix typo error

Correct the typo errors in json files

- "diffferent" is corrected to "different".
- "muliple" and "miltiple" is corrected to "multiple".

Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Karan Sanghavi <karansanghvi98@gmail.com>
Link: https://patch.msgid.link/20241022-multiple_spell_error-v2-1-7e5036506fe5@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>