If qtests are run in verbose mode (i.e. if --verbose CL argument
was provided) then print all environment variables to stdout
before running the individual tests.

It is common nowadays, at least being able to output all config
vectors in a build chain, especially if it is required to
investigate build- and test-issues on foreign/remote machines,
which includes environment variables. In the context of writing
new test cases this is also useful for finding out whether there
are already some existing options for common questions like is
there a preferred location for writing test files to? Is there
a maximum size for test data? Is there a deadline for running
tests?

Use qos_printf() instead of g_test_message() to avoid the latter
cluttering the output.

Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Message-Id: <21d77b33c578d80b5bba1068e61fd3562958b3c2.1611704181.git.qemu_oss@crudebyte.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>