[dev.typeparams] all: merge master (46fd547d) into dev.typeparams

Conflicts:

- src/go/types/check_test.go

  CL 324730 on dev.typeparams changed the directory paths in TestCheck,
  TestExamples, and TestFixedbugs and renamed checkFiles to testFiles;
  whereas CL 337529 on master added a new test case just above them and
  that used checkFiles.

Merge List:

+ 2021-08-12 46fd547d internal/goversion: update Version to 1.18
+ 2021-08-12 5805efc7 doc/go1.17: remove draft notice
+ 2021-08-12 39634e7d CONTRIBUTORS: update for the Go 1.17 release
+ 2021-08-12 095bb790 os/exec: re-enable LookPathTest/16
+ 2021-08-11 dea23e9c src/make.*: make --no-clean flag a no-op that prints a warning
+ 2021-08-11 d4c0ed26 doc/go1.17: linker passes -I to extld as -Wl,--dynamic-linker
+ 2021-08-10 1f9c9d85 doc: use "high address/low address" instead of "top/bottom"
+ 2021-08-09 f1dce319 cmd/go: with -mod=vendor, don't panic if there are duplicate requirements
+ 2021-08-09 7aeaad5c runtime/cgo: when using msan explicitly unpoison cgoCallers
+ 2021-08-08 507cc341 doc: add example for conversion from slice expressions to array ptr
+ 2021-08-07 891547e2 doc/go1.17: fix a typo introduced in CL 335135
+ 2021-08-06 8eaf4d16 make.bash: do not overwrite GO_LDSO if already set
+ 2021-08-06 63b968f4 doc/go1.17: clarify Modules changes
+ 2021-08-06 70546f64 runtime: allow arm64 SEH to be called if illegal instruction
+ 2021-08-05 fd45e267 runtime: warn that KeepAlive is not an unsafe.Pointer workaround
+ 2021-08-04 6e738868 net/http: speed up and deflake TestCancelRequestWhenSharingConnection
+ 2021-08-02 8a7ee4c5 io/fs: don't use absolute path in DirEntry.Name doc
+ 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

Change-Id: Ia80604d24c6f4205265683024e3100769cf32065