fix: Fix dividing zero error in validateFloatError
fix: Fix dividing zero error in validateFloatError

The error would happen under the following situation:

For the parameter t[_i] and f_i are both zero, TEST_SUCCESS should be
returned, but df_i is gotten by dividing f_i. Therefore, df_i would be
NaN instead of zero.

close #514

DLTcollab/sse2neon,DLTcollab/sse2neon,DLTcollab/sse2neon