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 =