[fir] TargetRewrite: Rewrite COMPLEX values

Rewrite function signatures and calls to functions that accept or return
COMPLEX values.

Also teach insert_value and extract_value about the MLIR ComplexType, by
adding AnyComplex to AnyCompositeLike.

This patch is part of the effort for upstreaming the fir-dev branch.

Differential Revision: https://reviews.llvm.org/D113273



Co-authored-by: Eric Schweitz <eschweitz@nvidia.com>
Co-authored-by: Kiran Chandramohan <kiran.chandramohan@arm.com>
Co-authored-by: Tim Keith <tkeith@nvidia.com>
Co-authored-by: Jean Perier <jperier@nvidia.com>