Automated g4 rollback of changelist 885555524.

*** Reason for rollback ***

Rolling back obj/stl decoder inclusion as sources due to broken windows build.

*** Original change description ***

Include obj and stl decoder plugins as sources in CMake builds.

This removes the need to load these decoders via mj_loadAllPluginLibraries when using MuJoCo built with CMake. Other plugins are unchanged.

***

PiperOrigin-RevId: 885576586
Change-Id: I31e6fa4d10697862f7d800d0d771ca752747e36d

test/xml/CMakeLists.txt

@@ -16,6 +16,9 @@ mujoco_test(xml_api_test)
 
 mujoco_test(
   xml_native_reader_test
+  PROPERTIES
+  ENVIRONMENT
+  "MUJOCO_PLUGIN_DIR=$<TARGET_FILE_DIR:obj_decoder>"
 )
 
 mujoco_test(xml_utils_test)