Ensure we decont into a fresh register.
Ensure we decont into a fresh register.

In cases where we actually get a register that is persistent (such as
holding a local that a lexical was lowered into), we should not go
and ruin the variable.

cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp