Incorrect bank used in unsigned long multiplication under certain circumstances.
Steps to reproduce:
This has been seen when __mul_32u__0000F_arg_a is in bank 0, and __mul_32u__0000F_arg_b and __mul_32u__0000F_1_i are in bank 1.
In the compiled code, in the calling function, bank 1 is selected, __mul_32u__0000F_arg_b is set up, bank 0 is selected, __mul_32u__0000F_arg_a is set up, and __mul_32u__0000F is called while still in bank 0. __mul_32u__0000F assumes that it is already in bank 1 on calling, clears __mul_32u__0000F_1_i, then clears RP0 (although it is already