[Buildsystem] Improve cache handling

(cherry picked from commit 24118b9ddc)

SConstruct

@@ -796,12 +796,13 @@ elif selected_platform != "":
 
 # The following only makes sense when the 'env' is defined, and assumes it is.
 if "env" in locals():
-    # FIXME: This method mixes both cosmetic progress stuff and cache handling...
     methods.show_progress(env)
     # TODO: replace this with `env.Dump(format="json")`
     # once we start requiring SCons 4.0 as min version.
     methods.dump(env)
 
+    methods.clean_cache(env)
+
 
 def print_elapsed_time():
     elapsed_time_sec = round(time.time() - time_at_start, 3)