[dev.typeparams] all: merge master (296ddf2a) into dev.typeparams

Conflicts:

- src/runtime/runtime2.go

  On master, CL 317191 fixed the mentions of gc/reflect.go in comments
  to reflectdata/reflect.go; but on dev.typeparams, CL 325921 fixed
  that the same comment to reflect that deferstruct actually ended up
  in ssagen/ssa.go.

Merge List:

+ 2021-07-08 296ddf2a net: filter bad names from Lookup functions instead of hard failing
+ 2021-07-08 ce76298e Update oudated comment
+ 2021-07-08 2ca44fe2 doc/go1.17: linkify time.UnixMilli and time.UnixMicro
+ 2021-07-07 5c59e11f cmd/compile: remove special-casing of blank in types.sconv{,2}
+ 2021-07-07 b003a8b1 cmd/compile: optimize types.sconv
+ 2021-07-07 11f5df2d cmd/compile: extract pkgqual from symfmt
+ 2021-07-07 991fd381 cmd/go: don't lock .mod and .sum files for read in overlay
+ 2021-07-07 186a3bb4 cmd/go/internal/modfetch/codehost: skip hg tests if no hg binary is present
+ 2021-07-07 00c00558 cmd/go/internal/modload: remove unused functions
+ 2021-07-07 f264879f cmd/go/internal/modload: fix an apparent typo in the AutoRoot comment
+ 2021-07-07 c96833e5 doc: remove stale comment about arm64 port

Change-Id: I849046b6d8f7421f60323549f3f763ef418bf9e7