scripts: add STATE logging level for state save/restore output.

The save/restore state output is voluminous; using this flag allows us
to quickly see or ignore when something is just being saved.

[Yann E. MORIN: this is a blind log level, and is used only to search
in the build-log afterward.]

Signed-off-by: Anthony Foiani <anthony.foiani@gmail.com>

# 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 =