Don't replace `TruncateFloat64ToInt32(RoundInt64ToFloat64(value))` with
`value`. Generally, `value` may have a range bigger than the one that
could fit into Int32. Replace it with `TruncateInt64ToInt32(value)`
instead, and only if the `value` fits into Float64 without precision
loss.

Add missing mjsunit test for 52bit multiplication/division optimization
that has landed in refs/heads/master@{#31899}.

BUG=
R=titzer@google.com

Review URL: https://codereview.chromium.org/1433353006

Cr-Commit-Position: refs/heads/master@{#32227}