fix(core): correct ticks_diff arguments' order

[no changelog]

Author: romanz

core/mocks/utime.pyi

@@ -5,5 +5,5 @@ def ticks_ms() -> int: ...
 def ticks_us() -> int: ...
 def ticks_cpu() -> int: ...
 def ticks_add(ticks_in: int, delta_in: int) -> int: ...
-def ticks_diff(old: int, new: int) -> int: ...
+def ticks_diff(new: int, old: int) -> int: ...
 def gmtime2000(timestamp: int) -> tuple: ...