devtools: rename build test verbosity variables
devtools: rename build test verbosity variables

The verbosity was meant to be set with options -v and -vv,
or possibly with the environment variables TEST_MESON_BUILD_VERBOSE
and TEST_MESON_BUILD_VERY_VERBOSE.

It is decided to keep only the options -v and -vv,
so the variables are renamed with lower case, marking them as privates.

The handling of the verbosity level is also moved upper in the script,
closer to other initializations.

Signed-off-by: Thomas Monjalon <5f50a84c1fa3bcff146405017f36aec1a10a9e38@monjalon.net>
Reviewed-by: David Marchand <f28529695cfa9e3e1eb84e7072aa626af4abb18e@redhat.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk