fix DexMerger's estimate for the merged classData section

the new estimated growth factor of 1.67 is derived as follows:
- classData section contains fields and methods
- for each method, 3 ulebs are written, but one of them (modifiers) doesn't
  change as a result of merging
- for each field, 2 ulebs are written, but one can again not change
- thus in the worst case, the section only contains methods and every 2/3
  ulebs can grow

(cherry picked from commit 89c573adfb3e9075b373e7ca324700e13971e918)

Bug: 27368018

Change-Id: I1dddc419592c8cd39d98c703840316d0ab65120c
1 file changed