[release-branch.go1.17] all: merge master (b8ca6e59) into release-branch.go1.17

Merge List:

+ 2021-07-31 b8ca6e59 all: gofmt
+ 2021-07-30 b7a85e00 net/http/httputil: close incoming ReverseProxy request body
+ 2021-07-29 70fd4e47 runtime: avoid possible preemption when returning from Go to C
+ 2021-07-28 9eee0ed4 cmd/go: fix go.mod file name printed in error messages for replacements
+ 2021-07-28 b39e0f46 runtime: don't crash on nil pointers in checkptrAlignment
+ 2021-07-27 7cd10c11 cmd/go: use .mod instead of .zip to determine if version has go.mod file
+ 2021-07-27 c8cf0f74 cmd/go: add missing flag in UsageLine
+ 2021-07-27 7ba8e796 testing: clarify T.Name returns a distinct name of the running test
+ 2021-07-27 33ff1559 go/types: preserve untyped constants on the RHS of a shift expression
+ 2021-07-26 840e583f runtime: correct variable name in comment
+ 2021-07-26 bfbb2885 runtime: remove adjustTimers counter
+ 2021-07-26 9c81fd53 cmd/vet: add missing copyright header
+ 2021-07-26 ecaa6816 doc: clarify non-nil zero length slice to array pointer conversion
+ 2021-07-26 1868f829 crypto/x509: update iOS bundled roots to version 55188.120.1.0.1
+ 2021-07-25 849b7911 spec: use consistent capitalization for rune literal hex constants
+ 2021-07-23 0914646a doc/1.17: fix two dead rfc links
+ 2021-07-22 052da571 cmd/compile: do not change field offset in ABI analysis
+ 2021-07-22 798ec735 runtime: don't clear timerModifiedEarliest if adjustTimers is 0
+ 2021-07-22 fdb45acd runtime: move mem profile sampling into m-acquired section
+ 2021-07-21 3e48c038 reflect: add missing copyright header
+ 2021-07-21 48c88f1b reflect: add Value.CanConvert
+ 2021-07-20 9e265692 cmd/go: don't add C compiler ID to hash for standard library
+ 2021-07-20 d568e6e0 runtime/debug: skip TestPanicOnFault on netbsd/arm
+ 2021-07-19 c8f4e615 spec: correct example comment in Conversions from slice to array
+ 2021-07-19 1d91551b time: correct typo in documentation for UnixMicro
+ 2021-07-19 404127c3 cmd/compile: fix off-by-one error in traceback argument counting
+ 2021-07-19 6298cfe6 cmd/compile: fix typo in fatal message of builtinCall
+ 2021-07-19 49402bee cmd/{compile,link}: fix bug in map.zero handling
+ 2021-07-18 a66190ec test/bench/go1: fix size for RegexpMatchMedium_32
+ 2021-07-18 650fc211 text/scanner: use Go convention in Position doc comment
+ 2021-07-16 aa4e0f52 net/http:  correct capitalization in cancelTimeBody comment
+ 2021-07-15 0941dbca testing: clarify in docs that TestMain is advanced
+ 2021-07-15 69728ead cmd/go: update error messages in tests to match CL 332573
+ 2021-07-15 c1cc9f9c cmd/compile: fix lookup package of redeclared dot import symbol
+ 2021-07-15 21a04e33 doc/go1.17: mention GOARCH=loong64
+ 2021-07-14 2b00a54b go/build, runtime/internal/sys: reserve GOARCH=loong64
+ 2021-07-14 60ddf42b cmd/go: change link in error message from /wiki to /doc.
+ 2021-07-13 d8f348a5 cmd/go: remove a duplicated word from 'go help mod graph'

Change-Id: I63a540ba823bcbde7249348999ac5a7d9908b531