Unit test framework for phosphor-debug-collector

Change:
-Serialize method does not use any of the watch functionalities,
so defining set in serialization header as using watch header
creates unnecessary dependency.

Test:
Added 3 test cases related to dump serialization.
Ran the UTs on docker environment.

Result:
1/1 debug_inif_test OK             1.48s

Ok:                 1
Expected Fail:      0
Fail:               0
Unexpected Pass:    0
Skipped:            0
Timeout:            0

Signed-off-by: Chirag Sharma <chirshar@in.ibm.com>
Change-Id: I6a88559bf407fa70a96dda3b31aaa1acd038c958