Add new Doclava flag support to soong

CL I8fe27e8c03334f9c90204db1e69447de65a06a38 adds new "-removedDexApi"
flag to Doclava. This patch adds support for that flag into Soong.
"droiddoc" targets can generate the new API file with property
"removed_dex_api_filename".

Bug: 78182899
Test: make
Change-Id: I04b8f615aa4655167b824d40c3fafa2648beec01