[tests] update oracles according to various recent kernel changes

 - fix indentation
 - follow the model of must_init, build_initializer
 - only generated code if generate is set,
 - generate code "on project".
 - rename mainargs.i -> mainargs.c

also change gcc_test.sh so that one can pass arguments to program
under test.

[quantif] updated according to AST changes: && is now left-associative

update code and oracles according to Frama-C changes, in particular interpretation of \valid in presence of const