Remove field offsets from g-ir-generate output and test inputs

Remove field offsets from g-ir-generate output and test inputs

Field offsets are a) architecture dependent so they shouldn't be part
of the architecture-independent gir format which is installed in
datadir. b) Are architecture-dependent so they shouldn't be in test
expected output. Remove field offsets from girs.
(Virtual function and discriminator offsets are not removed, as they
aren't fully hooked up to the field-offset computation machinery yet.)

svn path=/trunk/; revision=877