gdb.base/scope.exp: Remove bogus gdb_test questions

This test is abusing the QUESTION/RESPONSE feature to send an
alternative command to GDB if the first command fails.  Like so:

   gdb_test "print 'scope0.c'::filelocal" \
	    "\\\$$decimal = 1" "print 'scope0.c'::filelocal at main" \
	    "No symbol \"scope0.c\" in current context.*" \
	    "print '$srcdir/$subdir/scope0.c'::filelocal"

So if 'scope0.c' doesn't work, we try again with
'$srcdir/$subdir/scope0.c'.  I strongly suspect this is really an
obsolete test.  I think that if '$srcdir/$subdir/scope0.c' works, then
'scope0.c' should have worked too, thus I'd think that if we pass due
to the question path, then it's a bug.  So just remove the question
part passed to gdb_test.

Change-Id: I2acc99285f1d519284051b49693b5441fbdfe3cd