add an optional, less-accurate-but-faster sprite render and fix silly math bug (#1102)

* also add a new sprite renderer

* claaaang

* goal build fix

* fix tests, add stack singleton option

* make all event-message-blocks the same

* diskboot

test/decompiler/reference/kernel/gkernel-h_REF.gc

@@ -327,6 +327,7 @@
    (message    symbol    :offset-assert  12)
    (param      uint64  7 :offset-assert  16)
    )
+  :always-stack-singleton
   :method-count-assert 9
   :size-assert         #x48
   :flag-assert         #x900000048