releasetools: don't create prebuilt_dir path if it exits

This path may already exists from previous build tasks. Attempting
to create it again will cause an error.

Change-Id: I4baad8bc846470b99f6ce9207c0682401406decc
build: Degreenify java

Change-Id: Iac348407997f7e52844af0494ee59762df0819d7
languages_full: Remove duplicate Hindi inclusion

Change-Id: If9138e4b8980cacb37a7029ff42822faab63796e
build: Refactor additional languages/locales

Change-Id: Id90911405f98c5e44d1e5faf071135b8fe59925c
build: Add support for Uyghur

Change-Id: I29fe330daa205f800d4de5c92beae39fca44910d
build: Add support for Tamil

Change-Id: Ied26a54e36ef95e11f33600f925931f962798d32