Fix for MemoryOnBoot regression.

This change:
- removes overly broad keep rules for R.class and Apache compress
  library
- add specific keep rules generated from running trace references

Previously, test failures occurred due to removal of static fields from
R.class and Apache compress library during optimization. To resolve this
broad keep rules were added to proguard.flags, leading to increase in
app size. This change replaces those rules with more targeted ones.

Test: atest DocumentsUIGoogleTests
Bug: 339312616
Flag: EXEMPT bugfix
Change-Id: I23b867ec2a8b6281a57f840b95b2adbb8ec73655