remove unused variables from bin.cpp

[jmoralez]

Removes unused variables from bin.cpp. Addresses the following warnings:

io/bin.cpp:165:9: warning: variable 'cnt_zero' set but not used [-Wunused-but-set-variable]
    int cnt_zero = 0;
        ^
io/bin.cpp:164:9: warning: variable 'left_cnt_data' set but not used [-Wunused-but-set-variable]
    int left_cnt_data = 0;
        ^
io/bin.cpp:166:9: warning: variable 'right_cnt_data' set but not used [-Wunused-but-set-variable]
    int right_cnt_data = 0;
        ^

Sample logs

[jameslamb]

oh wow, nice find! Thank you.

[github-actions]

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