Add function ParamForLoop* toParamForLoop(BaseAST* a)
Implement ParamForLoop::copy()
Implement a function that produces a copy of the body, a BlockStmt, of a ParamForLoop
Simplify BlockStmt::isLoopStmt()
Add a short-circuit for ParamForLoop to isDefinedAllPaths()
Clarify use of blockInfoGet() in is_param_resolved()
In fold_param_for 1) Clarify that block is in fact a ParamForLoop 2) Copy the body of the ParamForLoop as a BlockStmt