tests: CMakeLists.txt: move test names to variable

The intent is to be able to disable some features that get built into the
library. When we do that, we also need to disable some tests.

It's easier when adjusting a variable that contains the list of test names,
versus modifying the list in the foreach() statement.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>

tests/CMakeLists.txt

@@ -12,7 +12,7 @@ target_link_libraries(test2Formatted PRIVATE ${PROJECT_NAME})
 
 include_directories(PUBLIC ${CMAKE_SOURCE_DIR})
 
-foreach(TESTNAME
+set(ALL_TEST_NAMES
     test1
     test2
     test4
@@ -37,6 +37,8 @@ foreach(TESTNAME
     test_visit
     test_object_iterator)
 
+foreach(TESTNAME ${ALL_TEST_NAMES})
+
 add_executable(${TESTNAME} ${TESTNAME}.c)
 if(${TESTNAME} STREQUAL test_strerror OR ${TESTNAME} STREQUAL test_util_file)
 # For output consistency, we need _json_c_strerror() in some tests: