Simplifying slightly the logic in the cmake (#1219)

CMakeLists.txt

@@ -21,20 +21,15 @@ include(cmake/simdjson-user-cmakecache.cmake)
 
 if(SIMDJSON_JUST_LIBRARY)
   message( STATUS "Building just the library, omitting all tests, tools and benchmarks." )
-endif()
-
-#
-# Set up test data
-#
-if(NOT(SIMDJSON_JUST_LIBRARY))
+else(SIMDJSON_JUST_LIBRARY)
+  # Setup tests
   enable_testing()
   add_subdirectory(jsonchecker)
   add_subdirectory(jsonexamples)
   add_library(test-data INTERFACE)
   target_link_libraries(test-data INTERFACE jsonchecker-data jsonchecker-minefield-data jsonexamples-data)
-endif()
+endif(SIMDJSON_JUST_LIBRARY)
 
-#
 # Create the top level simdjson library (must be done at this level to use both src/ and include/
 # directories) and tools
 #