[mock_tests]: Add CoPP Orch UTs. (sonic-net#2253)

Added CoPP UTs to increase code/feature coverage
Signed-off-by: Nazarii Hnydyn <[email protected]>

Author: nazariig

tests/mock_tests/Makefile.am

@@ -26,6 +26,7 @@ tests_SOURCES = aclorch_ut.cpp \
                 routeorch_ut.cpp \
                 qosorch_ut.cpp \
                 bufferorch_ut.cpp \
+                copporch_ut.cpp \
                 saispy_ut.cpp \
                 consumer_ut.cpp \
                 ut_saihelper.cpp \