Better Unit Tests - Runs All Of Them On A Single Map (exc. map unit tests) and C&D Split-Up (#96368)

## About The Pull Request

### Don't run every single test

I've had this on my mind for several months and it being brought up
recently reminded me so here we are.

Unit tests only run on `runtimestation_minimal.dmm` now with the
exception of map tests. The following unit tests are declared as map
tests but I didn't see any map dependent logic so 🤷
- `/datum/unit_test/maptest_baseturfs_unmodified_scrape`
- `/datum/unit_test/maptest_baseturfs_placed_on_top`
- `/datum/unit_test/maptest_baseturfs_placed_on_bottom`
- `/datum/unit_test/maptest_get_turf_pixel`
- `/datum/unit_test/maptest_load_map_security`
- `/datum/unit_test/maptest_modular_map_loader`
- `/datum/unit_test/maptest_turf_icons`

`/datum/unit_test/subsystem_init` isn't really a mapping unit test but I
figured somehow, someway, maps might fuck with subsystem initializations
so I just decided to include it.

### Splits up the create & destroy test

Idk, pretty simple. Create & destroy is now split up across all
integration tests and ran in parallel.

## Why It's Good For The Game

oranges promised me "500 nzd" yo

## Changelog

No player facing changes

code/datums/map_config.dm

@@ -60,8 +60,12 @@
 	/// Boolean - if TRUE, players spawn with grappling hooks in their bags
 	var/give_players_hooks = FALSE
 
+#if defined(UNIT_TESTS) || defined(SPACEMAN_DMM)
 	/// List of unit tests that are skipped when running this map
 	var/list/skipped_tests
+	/// If TRUE, only unit tests with UNIT_TEST_DEBUG_MAP_ONLY will run on this map
+	var/is_unit_test_map = FALSE
+#endif
 
 	/// Boolean that tells SSmapping to load all away missions in the codebase.
 	var/load_all_away_missions = FALSE
@@ -266,6 +270,9 @@
 			stack_trace("Invalid path in mapping config for ignored unit tests: \[[path_as_text]\]")
 			continue
 		LAZYADD(skipped_tests, path_real)
+
+	if ("is_unit_test_map" in json)
+		is_unit_test_map = json["is_unit_test_map"]
 #endif
 
 	defaulted = FALSE