Fix infinite loop found in consolidate_database

[dgets]

While working on the following data:

May 13, 2019, 11:46 a.m.: 5.000mg ouah (ouah)
May 1, 2019, noon: 5.000mg ouah (ouah)
July 6, 2019, 10:37 p.m.: 18.000mg caffeine (1,3,7-Trimethylxanthine Theine)
May 15, 2019, 7:30 p.m.: 0.250mg klonopin (clonazepam)
May 4, 2019, 8:36 p.m.: 0.250mg klonopin (clonazepam)
July 10, 2019, 10:21 a.m.: 18.000dose nicotine (C10H14N2)
July 10, 2019, 10:07 a.m.: 10.000dose nicotine (C10H14N2)
May 12, 2019, 8:15 p.m.: 10.000dose nicotine (C10H14N2)
May 1, 2019, 10 a.m.: 2.000dose nicotine (C10H14N2)
April 30, 2019, 6:46 p.m.: 2.000dose nicotine (C10H14N2)

with various different spans of time for both caffeine and nicotine an infinite loop was encountered. Will start digging up the specifics on it below.