Don't check for non-trash in MISC() accesses
Don't check for non-trash in MISC() accesses

Removes a sketchy debug check which would test a disengaged union
field just to make sure it had been overwritten with a valid value
before reading it.  Technically speaking, that's undefined behavior.

hostilefork/rebol,rgchris/ren-c,rgchris/ren-c,giuliolunati/ren-c,rgchris/ren-c,hostilefork/rebol,rgchris/ren-c,rgchris/ren-c,hostilefork/rebol,giuliolunati/ren-c,giuliolunati/ren-c,hostilefork/rebol,giuliolunati/ren-c,hostilefork/rebol,hostilefork/rebol,giuliolunati/ren-c