OptimizeInstructions: Fix static cast optimizations (#4311)

We found one cast that has another as its input, and forgot that
the child was possibly a fallthrough value. That is, there might be more
code that needs to be kept around.

Rather than fix the middle of the three cases there - the one with
HeapType::isSubType(childIntendedType, intendedType) - I
noticed it is not actually needed. That case checks if the child's
type is more specific than the parent's, and if so, then the parent
is not needed. But we already handle that earlier above in the
same function: regardless of what the child of a static cast is,
if the cast is static and the input is the proper type already, the
cast is unneeded (see lines 1565-1566).

0 files changed, 0 insertions, 0 deletions