codegen: Initialize internal temp-variables used as reference parameter
codegen: Initialize internal temp-variables used as reference parameter

Variables for delegate-targets and array-lengths passed as reference in
method calls should be initialized to fix "make check" with -O3.

GNOME/vala,frida/vala,frida/vala,frida/vala,GNOME/vala,GNOME/vala,frida/vala,GNOME/vala,frida/vala