Remove unused classes and stray headers

Found by reviewing headers with 1 or less matching includes:
```
find -name thirdparty -prune -o -name "*.h" -exec basename {} \; | sort -u > headers
for header in $(cat headers); do echo "$header: "; rg -l "#include \"(.*/)?$header\"" | wc -l; done > list-includes
```

6 files changed, 11 insertions, 5 deletions

diff --git a/main/tests/test_main.cpp b/main/tests/test_main.cpp
index 2c2e6e8b45..beb955d045 100644
--- a/main/tests/test_main.cpp
+++ b/main/tests/test_main.cpp
@@ -28,8 +28,9 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
+#include "test_main.h"
+
 #include "core/list.h"
-#include "core/os/main_loop.h"
 
 #ifdef DEBUG_ENABLED
 
diff --git a/main/tests/test_main.h b/main/tests/test_main.h
index 56db3ea2a5..bdb1668d21 100644
--- a/main/tests/test_main.h
+++ b/main/tests/test_main.h
@@ -32,9 +32,10 @@
 #define TEST_MAIN_H
 
 #include "core/list.h"
+#include "core/os/main_loop.h"
 #include "core/ustring.h"
 
 const char **tests_get_names();
 MainLoop *test_main(String p_test, const List<String> &p_args);
 
-#endif
+#endif // TEST_MAIN_H
diff --git a/main/tests/test_oa_hash_map.cpp b/main/tests/test_oa_hash_map.cpp
index edb57f2a9f..ac53f124d2 100644
--- a/main/tests/test_oa_hash_map.cpp
+++ b/main/tests/test_oa_hash_map.cpp
@@ -30,9 +30,8 @@
 
 #include "test_oa_hash_map.h"
 
-#include "core/os/os.h"
-
 #include "core/oa_hash_map.h"
+#include "core/os/os.h"
 
 namespace TestOAHashMap {
 
diff --git a/main/tests/test_oa_hash_map.h b/main/tests/test_oa_hash_map.h
index 60cde961c5..eb2b3d1e99 100644
--- a/main/tests/test_oa_hash_map.h
+++ b/main/tests/test_oa_hash_map.h
@@ -37,4 +37,5 @@ namespace TestOAHashMap {
 
 MainLoop *test();
 }
+
 #endif // TEST_OA_HASH_MAP_H
diff --git a/main/tests/test_ordered_hash_map.cpp b/main/tests/test_ordered_hash_map.cpp
index cc779119bc..a5553217e2 100644
--- a/main/tests/test_ordered_hash_map.cpp
+++ b/main/tests/test_ordered_hash_map.cpp
@@ -28,6 +28,8 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
+#include "test_ordered_hash_map.h"
+
 #include "core/ordered_hash_map.h"
 #include "core/os/os.h"
 #include "core/pair.h"
diff --git a/main/tests/test_ordered_hash_map.h b/main/tests/test_ordered_hash_map.h
index 03e559107e..f251da0ba2 100644
--- a/main/tests/test_ordered_hash_map.h
+++ b/main/tests/test_ordered_hash_map.h
@@ -31,9 +31,11 @@
 #ifndef TEST_ORDERED_HASH_MAP_H
 #define TEST_ORDERED_HASH_MAP_H
 
+#include "core/os/main_loop.h"
+
 namespace TestOrderedHashMap {
 
 MainLoop *test();
 }
 
-#endif
+#endif // TEST_ORDERED_HASH_MAP_H