Merge pull request #2005 from YosysHQ/claire/fix1990

Add "nowrshmsk" attribute, fix shift-and-mask bit slice write for signed offset

diff --cc frontends/ast/genrtlil.cc
Simple merge

diff --cc frontends/ast/simplify.cc
Simple merge

diff --cc frontends/verilog/verilog_parser.y
Simple merge

diff --cc kernel/constids.inc
Simple merge