fix obviously bogus (IMO) operand index of the load in asserts

fix obviously bogus (IMO) operand index of the load in asserts
(load only has one operand) and smuggle in some whitespace changes too

NB: I am obviously testing the water here, and believe that the unguarded
    cast is still wrong, but why is the getZExtValue of the load's operand
    tested against zero here? Any review is appreciated.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155190 91177308-0d34-0410-b5e6-96231b3b80d8