[dev.typeparams] all: merge master (82127078) into dev.typeparams

Conflicts:

- src/go/internal/gcimporter/iimport.go

  CL 325429 and CL 319931 made unrelated changes to adjacent lines

Merge List:

+ 2021-06-07 82127078 crypto/elliptic: update P-521 docs to say it's constant-time
+ 2021-06-07 74061800 fmt: split package documentation into more sections
+ 2021-06-07 e3176bbc crypto/tls: fix typo in Config.NextProtos docs
+ 2021-06-05 e1fa2602 spec: improve wording consistency by eliminating "specifier"
+ 2021-06-05 f4901341 spec: improve wording by choosing an official term "keyword"
+ 2021-06-05 e3cb3817 go/internal/gcimporter: don't waste CPU copying bytes in `io.ReadAll`
+ 2021-06-05 9d669ed4 misc/cgo/errors: use expected column numbers
+ 2021-06-04 95939e8d cmd/compile/internal/abi: fix typo in comment
+ 2021-06-04 831f9376 net/http: fix ResponseWriter.ReadFrom with short reads
+ 2021-06-04 3a9d906e os: avoid finalizer race in windows process object
+ 2021-06-04 105c5b50 os: terminate windows processes via handle directly
+ 2021-06-04 79cd407f syscall: regenerate zsyscall_windows.go
+ 2021-06-04 c6b62112 doc/go1.17: document testing changes for Go 1.17
+ 2021-06-04 02144400 syscall: do not pass console handles to PROC_THREAD_ATTRIBUTE_HANDLE_LIST on Windows 7
+ 2021-06-04 962d5c99 cmd/compile,go/types: restrict use of unsafe.{Add,Slice} to go1.17 or newer
+ 2021-06-04 b29b123e cmd/compile: remove spurious ir.Dump
+ 2021-06-03 6d983011 cmd/link: use correct alignment in PE DWARF sections
+ 2021-06-03 e0d029f7 runtime: avoid gp.lockedm race in exitsyscall0
+ 2021-06-02 dd7ba3ba net: don't rely on system hosts in TestCVE202133195
+ 2021-06-02 4f572d70 io/fs: minor corrections to Sub docs
+ 2021-06-02 e11d1422 doc/go1.17: remove runtime section
+ 2021-06-02 6e189afd doc/go1.17: mention SYS_WAIT6/WEXITED on NetBSD
+ 2021-06-02 ff9f5fb8 cmd/link: recognize clang linker error in testCGOLTO
+ 2021-06-02 1c6a2ea2 doc/go1.17: document time changes for Go1.17
+ 2021-06-02 d743e67e doc/go1.17: document flag changes for Go 1.17
+ 2021-06-02 dc8f87b7 runtime/internal/sys: generate //go:build lines in gengoos.go
+ 2021-06-02 84c0e5d4 cmd/link: move issue 43830 tests out of TestScript
+ 2021-06-02 cae68700 runtime: fix formatting
+ 2021-06-01 567ee865 cmd/go: add declaration to cgo_lto_issue43830 test
+ 2021-06-01 24e9707c cmd/link, cmd/cgo: support -flto in CFLAGS

Change-Id: I9ef88e7de0f8b1841ed9604b613b41672df67e71