Create unit tests for HTPP category data fit with tcplfit2

[sedavid01]

Goal: The goal of this issue is to create unit tests for high-phenotypic profiling (HTPP) data such that we ensure that as the codebase of tcplfit2 is updated that the updates do not break/alter the results previously obtained in previous analyses with tcplfit2.

Needs for finishing this ticket:

• Choose a manageable subset of the overall data provided by the HTTR team - verify the chosen set covers many (if not all) scenarios of interest
• Create an RData file for the package (may want to ensure we do NOT want this to be exported from the package)
• Create a unit test ensuring that the results for HTTR remain consistent from version to version of tcplfit2

[sedavid01]

Update on dropped doses for HTPP data:

• Write a brief explanatory comment about the dropped doses
• Verify you are dropping the appropriate doses and number of doses for the respective chemicals
  (Note, suggesting to do the dropping the unit test code not in the data prep R script.)