Fix assert in diy_float
Fix assert in diy_float

The shifting should have gone the other way, the current incarnation is always true.
graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust