[dev.simd] all: merge master (388e94d) into dev.simd

Conflicts:

- src/cmd/compile/internal/types2/stdlib_test.go
- src/go/types/stdlib_test.go

Merge List:

+ 2026-05-29 388e94dfbd encoding/json/v2: use option flags to signal presence of tags
+ 2026-05-29 38c30806f9 encoding/json: refactor tests to use string literals for error offset
+ 2026-05-29 eb343e2fa0 Revert "cmd/gofmt: fix symlink file truncation"
+ 2026-05-29 261c95496f encoding/gob: fix copy-paste bug
+ 2026-05-29 5d2a112176 cmd/api: include baseline goexperiment.* tool tags
+ 2026-05-29 783a68b572 cmd/asm,cmd/internal/obj/riscv: update references to RISC-V specification
+ 2026-05-29 687ce6f9af test/codegen: floating point constant loads for riscv64
+ 2026-05-29 5f711bfdb3 cmd/gofmt: fix symlink file truncation
+ 2026-05-29 d96f55fe49 crypto/tls: wrap KeyLogWriter errors w/ prefix
+ 2026-05-28 7e3a04fb91 doc/next: delete
+ 2026-05-28 029edaa882 api: promote next to go1.27
+ 2026-05-28 6421cb6565 doc: format net package release note
+ 2026-05-28 6449874f49 doc: inserted TODOs into 9-todo.md
+ 2026-05-28 3ef3b74c86 crypto/internal/rand: fix typo to cryptotest.SetGlobalRandom
+ 2026-05-28 b32177443d go/types, types2: first argument to copy must never be nil
+ 2026-05-28 9e53e2e2cc doc/next: add release notes for sizespecializedmalloc
+ 2026-05-28 594517bf2b runtime, cmd/link: add hall of shame linknames for some cgo symbols
+ 2026-05-28 66b64c1e2f go/types, cmd/compile: add simd/.../sgutil to the TestStdlib ignores
+ 2026-05-28 c7e6da5ca5 os: notify testlog from (*File).Chdir
+ 2026-05-28 47d5295532 encoding/json/v2: allow jsontext options for MarshalEncode and UnmarshalDecode
+ 2026-05-27 13e2cc87fa os: make tests pass even without Administrator account
+ 2026-05-27 6e808ba41a runtime: tolerate vendor suffixes in Linux kernel release strings
+ 2026-05-27 6366476e7f runtime: make concurrent map test less flaky
+ 2026-05-27 bcdf61fef4 runtime/race: build race detector linux/arm64 syso with no-outline-atomics
+ 2026-05-27 01d183b000 runtime: revert "always call slowpath for heap bits in span"
+ 2026-05-27 d01955d5d5 crypto/x509: split candidate hostname only once
+ 2026-05-27 4229cb1eda debug/gosym: mask bracketed expressions rather than remove them
+ 2026-05-27 f15c638314 encoding/json/jsontext: correct invalid namespace error
+ 2026-05-27 88deda24e0 encoding/json/jsontext: use consistent receiver
+ 2026-05-27 aae1bdb6d4 encoding/json/jsontext: remove ineffectual subtraction
+ 2026-05-27 286c12b1d1 debug/elf: add FuzzReader
+ 2026-05-26 0631db6336 log/slog: use encoding.TextAppender for text handlers
+ 2026-05-26 c74c040511 doc: document removal of asynctimerchan GODEBUG setting (update release notes)
+ 2026-05-26 ec37f78ca7 doc: document removal of gotypesalias GODEBUG setting (update release notes)
+ 2026-05-26 08bd667214 doc: document new struct literal field selectors (update release notes)
+ 2026-05-26 4960851b93 spec: added a few version references where they were missing
+ 2026-05-26 acd801c178 doc: document generalized function type inference (update release notes)
+ 2026-05-26 ee500cd074 doc: document generic methods (update release notes)
+ 2026-05-26 ef067283ce spec: permit function type inference to satisfy assignability
+ 2026-05-26 b5772a8d7c .github: update PULL_REQUEST_TEMPLATE to match the latest instruction
+ 2026-05-26 ff9a2de809 cmd/go/internal/work: add signpost to x/tools vet std test
+ 2026-05-26 a004b4b1b0 all: REVERSE MERGE dev.simd (0ac6a67) into master

Change-Id: I1a5f77541f57beb60fd86fbe3da54d278db2ae64