Use str_to_num for Number parameter

Current implemenation method 'value' convert all input parameters. But
should ignore type Number, because it may round value with float type.
Also this logic is already implemented in str_to_num method. This patch
forces NumberParam class to use str_to_num in value method.

Closes-Bug: #1323649

Change-Id: I7333cb4d6641d886cffb4812ceaa58db8d86c135
Merge "Use str_to_num for Number parameter"