Deals with missing chromosome arm values in the given data frame of large segments.
LargeMissingChrArms.RdFinds the missing chromosome arms and reinserts them into large_segments. Specifically,
the arms that large_segments doesn't have, but small_segments does. For each of the missing
values, we iterate through the large segments, and re-insert the small segments wherever
appropriate.
For example (first case in while loop), if the missing_chr_arm value is greater than the largest chr_arm in the arm column (i.e., max(large_segments,3)), then we should bind the small segments to the right of the large segments frame, since there are no more segments after this largest chr_arm. Note that we only bind the small segments within this missing_chr_arm.
Otherwise, missing_chr_arm <= than the largest chr_arm. In this case we care about which large
segment we're looping over (the value of i). If i = 1, i.e. the first segment, then we bind
the small segments to the left of the large segments: this is trivial. Otherwise, we fit the
small segments in between i-1 and i.