More printf de-duplication.

Just trivial use of macros.

The %s/%ls case in __find_arguments was backwards in the wide copy of
the code, but not problematically so because all pointers are the same
size anyway.

Bug: http://b/67371539
Test: ran tests
Change-Id: I8d34915d75ae5425c56c59510a16c328fc481d20