A later linker CL defines a function that needs to forward a printf format
and argument list to TRACE(), but there is no version of the TRACE macro
that works with a va_list. The CL also needs to check the verbosity level,
using a slow path if tracing is enabled, so define LINKER_VERBOSITY_xxx
macros.
Bug: none
Test: bionic unit tests
Change-Id: I578d36a12dc40f9a651956b4b09adc1a7c644e24