Execution context assign values with diferent lenghts

[rbran]

In execution, some times values are assigned to variables with a bigger len.

eg: 8bit value into 16bit variable

[rbran]

CPUs affected: HCS12, avr32a, avr8xmega, avr8eind, riscv.ilp32d, riscv.lp64d, V850, 6502, 65c02, CR16B, CR16C, z80, z180, HC08, HCS08, HC05, tricore, 6809, 6805, H6309, MCS96, TI_MSP430, TI_MSP430X, CP1600, m8c, 80251, 80390, 8051, mx51, sh-1, sh-2, sh-2a, pic16, pic16f, pic17c7xx, pic18, PIC24E, PIC24F, PIC24H, dsPIC30F, dsPIC33C, dsPIC33E, dsPIC33F.