SCons: Don't cache librarys

(cherry picked from commit 83c0f15ab9)

test/SConstruct

@@ -38,4 +38,5 @@ else:
         source=sources,
     )
 
+env.NoCache(library)
 Default(library)

tools/godotcpp.py

@@ -506,6 +506,7 @@ def _godot_cpp(env):
 
     if env["build_library"]:
         library = env.StaticLibrary(target=env.File("bin/%s" % library_name), source=sources)
+        env.NoCache(library)
         default_args = [library]
 
         # Add compiledb if the option is set