Implement Zicond extension (#3329)

* Instructions: sync from riscv-opcodes (add zicond)

* Zicond: implement czero.eqz, czero.nez

* Zicond: fix implementation

* Zicond: reduce code duplication

* Add ISA extension when using Zicond

* Fix ISA extensions ordering

(cherry picked from commit 62162c5e)