[dev.typeparams] all: merge dev.regabi (37f138df) into dev.typeparams

Conflicts:

* src/cmd/compile/fmtmap_test.go
* src/cmd/compile/internal/gc/go.go
* src/cmd/compile/internal/gc/main.go
* src/cmd/compile/internal/noder/noder.go

Merge List:

* 2020-12-23 37f138df [dev.regabi] cmd/compile: split out package test [generated]
* 2020-12-23 3d8a3cb0 [dev.regabi] cmd/compile: split out package pkginit [generated]
* 2020-12-23 3f04d964 [dev.regabi] cmd/compile: split up walkexpr1, walkstmt [generated]
* 2020-12-23 e4895ab4 [dev.regabi] cmd/compile: split out package walk [generated]
* 2020-12-23 01fd2d05 [dev.regabi] cmd/compile: split out package dwarfgen [generated]
* 2020-12-23 6c34d2f4 [dev.regabi] cmd/compile: split out package ssagen [generated]
* 2020-12-23 de65151e [dev.regabi] cmd/compile: split out package reflectdata [generated]
* 2020-12-23 4dfb5d91 [dev.regabi] cmd/compile: split out package staticdata [generated]
* 2020-12-23 fbc82f03 [dev.regabi] cmd/compile: split out package noder [generated]
* 2020-12-23 de454eef [dev.regabi] cmd/compile: split out package escape [generated]
* 2020-12-23 071ab0a1 [dev.regabi] cmd/compile: split out package liveness [generated]
* 2020-12-23 0ced5406 [dev.regabi] cmd/compile: split out package objw [generated]
* 2020-12-23 575fd6ff [dev.regabi] cmd/compile: split out package inline [generated]
* 2020-12-23 0256ba99 [dev.regabi] cmd/compile: split up typecheck1 [generated]
* 2020-12-23 b9693d76 [dev.regabi] cmd/compile: split out package typecheck [generated]
* 2020-12-23 dac0de37 [dev.regabi] cmd/compile: move type size calculations into package types [generated]
* 2020-12-23 527a1895 [dev.regabi] cmd/compile: move helpers into package ir [generated]
* 2020-12-23 65c4c6df [dev.regabi] cmd/compile: group known symbols, packages, names [generated]
* 2020-12-23 9ee30925 [dev.regabi] cmd/compile: move helpers into package types [generated]
* 2020-12-23 ead49578 [dev.regabi] cmd/compile: move helpers into package base [generated]
* 2020-12-23 440308ff [dev.regabi] cmd/compile: simplify Nodes usage [generated]
* 2020-12-23 f9d37372 [dev.regabi] cmd/compile: remove Left, Right etc methods [generated]
* 2020-12-23 14d66734 [dev.regabi] cmd/compile: remove Node.Left etc [generated]
* 2020-12-23 6f27d29b [dev.regabi] cmd/compile: remove ir.Nod [generated]
* 2020-12-23 69cf3908 [dev.regabi] cmd/compile: do not die in early base.FlushErrors

Change-Id: Ic4686e77c6ee38b3cd7d37fc7f3e93aaa9017b7a