Remove checkstyle from development/checkstyle.

Checkstyle was moved to prebuilts/checkstyle as it is a better
place for a prebuilt jar. All the usages of checkstyle.py in
PREUPLOAD.cfg files has been updated to use the correct checkstyle
and this change should not affect anyone.

Bug: 33078621
Test: none
Change-Id: Ib2e4272a4bea7d16cccdebaeb407acbd7193f248