Add Acc!! backend

[Mukundan314]

This PR adds a backend for Acc!!, an esoteric programming language centered around a single accumulator.

Due to the nature of Acc!!, all instructions experience significant slowdowns when operating with large memory addresses. Consequently, several tests that take more than 10 minutes to complete have been disabled. Additionally, the official interpreter automatically inserts missing newlines before EOF on stdin, which affects tests that read until EOF. Therefore, all such tests have also been disabled.

To determine if additional tests should be disabled, I have compiled a table of tests that take longer than a minute. Please review the table below and provide feedback on whether these tests should also be disabled:

array.c.eir.acc            0m52.767s
global_array.c.eir.acc     1m5.678s
func2.c.eir.acc            1m11.358s
func_ptr.c.eir.acc         1m5.136s
hello.c.eir.acc            2m7.707s
loop.c.eir.acc             4m2.989s
puts.c.eir.acc             4m24.472s
func.c.eir.acc             5m1.941s
logic_val.c.eir.acc        5m38.624s
increment.c.eir.acc        6m14.044s
malloc.c.eir.acc           8m2.808s

[shinh]

Thanks!!