SegString `strip` and `peel` throwing OOM exception when problem size > 10**4

[joshmarshall1]

Exact problem size will be dependent on machine size, but running both methods with an problem size larger than 10**4 produce an out of memory error

Reproducer:

    N = 10**5  # Might need increasing depending on machine
    a = ak.random_strings_uniform(8, 2**16, N)
    a.strip("a")  # a.peel("a")