`caliper-core`: add tests for `Message` classes (#1561) #46

Job	Run time
unit-tests / Unit Tests (18.x)	1m 8s
unit-tests / Unit Tests (20.x)	1m 3s
publish-caliper / Publish Caliper	1m 36s
coverage / Coverage Reports (caliper-core)	6s
coverage / Coverage Reports (caliper-fabric)	5s
coverage / Coverage Reports (generator-caliper)	8s
	4m 6s

Provide feedback