Remove coverage handling from CMake.

CMakeLists.txt

@@ -50,8 +50,6 @@ endif (WINDOWS)
 # Add a definition for the test library
 target_compile_definitions(CreatureLibTests PRIVATE TESTS_BUILD)
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} --coverage")
-
 if (EXISTS ${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
     include(${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
     conan_basic_setup()