binderRpcTest: -= tuple += named values

Tuple by index is hard to verify the same semantics
are preserved in all places, but when we get values
directly by name, local checks make it clear that
we use the same semantics everywhere.

This change supports optimizing these tests, so we
can easily select the combinations we want to run
later.

Bug: 292808096
Bug: 292820454
Test: binderRpcTest
Change-Id: I8cac77d631cd2bb7d5a4c47ae4bbc267b050b0ce