tests: Remove obsolete test; don't use fp in micropython/ tests.

tests/basics/class_subclass_builtin.py

-#class mylist(list):
-#    pass
-
-#l = mylist()
-#l.append(1)
-#print(l)

tests/micropython/native_const.py

@@ -5,9 +5,3 @@ def f():
     return 123456789012345678901234567890
 
 print(f())
-
-@micropython.native
-def g():
-    return 1.2
-
-print(g())

tests/micropython/native_const.py.exp

 123456789012345678901234567890
-1.2