Fix: filter-grammar-test: add dependencies between steps

If the user specifies only the -B switch of the filter-grammar-test
program, the program will try to print the bytecode without having
generated it first, leaving to a segfault.  Similarly, if the user
specifies only the -b switch, the program will try to generate the
bytecode from the IR, without having generated the IR first, also
leading to a segfault.

This patch adds some kind of dependency between the steps, such that if
the user is interested in a particular step (let's say, print the
bytecode), all the required steps will also be done.

Change-Id: Idc365a12b992a950566f227759fd3223cf5c5fd8
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>