decomp: eye (#778)

* decomp: `eye` close just need a pile of casts for the rendering code

* stash

* decomp: `eye` mostly cleaned up, xmm reg issue with `pextlb`

* waitin

* update ref tests and gsrc

* update reference tests

test/decompiler/reference/engine/draw/process-drawable_REF.gc

@@ -976,7 +976,7 @@
         (merc-blend-shape obj)
         )
     (if (logtest? (-> obj skel status) 384)
-        (merc-eye-anim obj)
+        (merc-eye-anim (the-as manipy obj))
         )
     (label cfg-27)
     (let ((a0-17 (-> gp-0 effect)))