Added legacy_by_exception_only to:
libwvdrmengine/test/castv2/Android.mk
libwvdrmengine/test/java/MediaDrmApiTest/Android.mk
Bug: 68860345
Bug: 151177513
Bug: 151953481
Test: m all
Exempt-From-Owner-Approval: janitorial work
Change-Id: I71c2aaa0efb3730f56863bc9047f8794e6a9de01