c-family: Fix up -fno-debug-cpp [PR111965]

c-family: Fix up -fno-debug-cpp [PR111965]

As can be seen in the second testcase, -fno-debug-cpp is actually
implemented the same as -fdebug-cpp and so doesn't turn the debugging
off.

The following patch fixes that.

2023-12-07  Andrew Pinski  <pinskia@gmail.com>
	    Jakub Jelinek  <jakub@redhat.com>

	PR preprocessor/111965
gcc/c-family/
	* c-opts.cc (c_common_handle_option) <case OPT_fdebug_cpp>: Set
	cpp_opts->debug to value rather than 1.
gcc/testsuite/
	* gcc.dg/cpp/pr111965-1.c: New test.
	* gcc.dg/cpp/pr111965-2.c: New test.