[scripts] Bug-fix: ensure allowed lengths all written as int (#3919)

Ensure that allowed lengths are all written as `int` as intended. This is required by downstream scripts like steps/nnet3/chain/e2e/get_egs_e2e.sh.

Author: vimalmanohar

egs/wsj/s5/utils/data/get_allowed_durations.py

@@ -180,7 +180,7 @@ def get_trivial_allowed_durations(utt2dur, args):
                      + args.frame_length + args.frame_shift / 2) / 1000.0
             allowed_durations.append(d)
             durs_fp.write("{}\n".format(d))
-            lengths_fp.write("{}\n".format(length))
+            lengths_fp.write("{}\n".format(int(length)))
 
     assert len(allowed_durations) > 0
     start_dur = allowed_durations[0]