[dev.typeparams] all: merge dev.regabi (07569dac) into dev.typeparams

Conflicts:

- test/fixedbugs/issue27595.go
- test/fixedbugs/issue30087.go
- test/used.go

Merge List:

+ 2020-12-28 07569dac [dev.regabi] all: merge master (1d781391) into dev.regabi
+ 2020-12-28 76136be0 [dev.regabi] cmd/compile: check for recursive import in ImportBody
+ 2020-12-28 fda7ec3a [dev.regabi] cmd/compile: remove Name.IsDDD, etc
+ 2020-12-28 098a6490 [dev.regabi] cmd/compile: remove Declare in makepartialcall
+ 2020-12-28 137f0d2e [dev.regabi] cmd/compile: remove unnecessary Name.Sym call
+ 2020-12-28 3383b5c7 [dev.regabi] cmd/compile: flatten dependency graph [generated]
+ 2020-12-28 f8afb821 [dev.regabi] cmd/compile: rename CommStmt and CaseStmt [generated]
+ 2020-12-28 5f3bd59a [dev.regabi] cmd/compile: remove some unneeded code in package ir
+ 2020-12-28 3bdafb0d [dev.regabi] cmd/compile: remove CommStmt.List
+ 2020-12-28 2ecf52b8 [dev.regabi] cmd/compile: separate CommStmt from CaseStmt
+ 2020-12-28 ed9772e1 [dev.regabi] cmd/compile: add explicit file name in types generation
+ 2020-12-28 a59d2660 [dev.regabi] cmd/compile: use []*CaseStmt in {Select,Switch}Stmt
+ 2020-12-28 fbc4458c [dev.regabi] cmd/compile: simplify some tree traversal code
+ 2020-12-28 6c676775 [dev.regabi] cmd/compile: simplify FuncName and PkgFuncName
+ 2020-12-28 676d794b [dev.regabi] cmd/compile: remove refersToCommonName
+ 2020-12-28 c98548e1 [dev.regabi] cmd/compile: merge ascompatee, ascompatee1, and reorder3
+ 2020-12-28 4c215c4f [dev.regabi] cmd/compile: simplify and optimize reorder3
+ 2020-12-28 e6c97319 [dev.regabi] cmd/compile: stop mangling SelectorExpr.Sel for ODOTMETH
+ 2020-12-28 135ce1c4 [dev.regabi] cmd/compile: desugar OMETHEXPR into ONAME during walk
+ 2020-12-28 0f732f8c [dev.regabi] cmd/compile: minor walkExpr cleanups
+ 2020-12-28 0de8eafd [dev.regabi] cmd/compile: remove SelectorExpr.Offset field
+ 2020-12-28 a4f335f4 [dev.regabi] cmd/compile: always use a Field for ODOTPTR expressions
+ 2020-12-26 1d781391 runtime/cgo: fix Android build with NDK 22
+ 2020-12-25 2018b68a net/mail: don't use MDT in test
+ 2020-12-25 e4f293d8 [dev.regabi] cmd/compile: fix OCALLMETH desugaring
+ 2020-12-25 1d9a1f67 [dev.regabi] cmd/compile: don't emit reflect data for method types
+ 2020-12-25 396b6c2e [dev.regabi] cmd/compile: cleanup assignment typechecking
+ 2020-12-25 e24d2f3d [dev.regabi] cmd/compile: remove typ from RangeStmt
+ 2020-12-25 2785c691 [dev.regabi] cmd/compile: cleanup devirtualization docs
+ 2020-12-25 4b1d0fe6 [dev.regabi] cmd/compile: new devirtualization pkg [generated]
+ 2020-12-24 082cc8b7 [dev.regabi] cmd/compile: change ir.IsAssignable -> ir.IsAddressable
+ 2020-12-24 27b248b3 [dev.regabi] cmd/compile: separate range stmt Vars to Key, Value nodes
+ 2020-12-23 40818038 [dev.regabi] cmd/compile: change CaseStmt.Vars to Var
+ 2020-12-23 b1164044 runtime: shift timeHistogram buckets and allow negative durations
+ 2020-12-23 8db7e2fe runtime: fix allocs-by-size and frees-by-size buckets
+ 2020-12-23 fb96f07e runtime: fix nStackRoots comment about stack roots
+ 2020-12-23 d1502b3c lib/time, time/tzdata: update tzdata to 2020e
+ 2020-12-23 30c99cbb cmd/go: add the Retract field to 'go help mod edit' definition of the GoMod struct
+ 2020-12-23 49d0b239 doc: fix a typo in contribute.html
+ 2020-12-23 9eeed291 [dev.regabi] cmd/compile: eliminate usage of ir.Node in liveness
+ 2020-12-23 d1d64e4c [dev.regabi] cmd/compile: split SliceExpr.List into separate fields
+ 2020-12-23 98a73030 cmd/go: in 'go get', promote named implicit dependencies to explicit
+ 2020-12-23 d19018e8 [dev.regabi] cmd/compile: split SliceHeaderExpr.LenCap into separate fields
+ 2020-12-23 53f082b0 [dev.regabi] cmd/compile: cleanup export code further
+ 2020-12-23 31267f82 [dev.regabi] cmd/compile: simplify function/interface/struct typechecking
+ 2020-12-23 addade2c [dev.regabi] cmd/compile: prefer types constructors over typecheck
+ 2020-12-23 18ebfb49 [dev.regabi] cmd/compile: cleanup noder
+ 2020-12-23 87a592b3 [dev.regabi] cmd/compile: cleanup import/export code
+ 2020-12-23 58980250 [dev.regabi] cmd/compile: update mkbuiltin.go to use new type constructors
+ 2020-12-23 63c96c2e [dev.regabi] cmd/compile: update mkbuiltin.go and re-enable TestBuiltin
+ 2020-12-23 fd6ba1c8 os/signal: fix a deadlock with syscall.AllThreadsSyscall() use
+ 2020-12-23 b0b0d982 runtime: linux iscgo support for not blocking nptl signals
+ 2020-12-22 223331fc cmd/go/internal/modload: add hint for missing implicit dependency

Change-Id: Iecb8a7dfb401b6ab383e97101cd81bfc201683f6