cc/gcc: do not print 'core' or 'final'

In gcc-'s core and final passes, do not print 'core' or 'final' in
log messages. We already print it in step messages.

Also, as we use the core backend to build the bare-metal final gcc,
it can be disturbing to read 'core' while we're in fact in 'final'.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

# Default test suite configuration

# Default DejaGnu configuration

DG_TOOLNAME = gcc

DG_TARGET_HOSTNAME = 127.0.0.1

DG_TARGET_USERNAME = root

# Default tests

DG_C_TESTS = 

DG_CPP_TESTS =