[dev.typeparams] all: merge dev.regabi (5e4a0cd) into dev.typeparams

Merge List:

+ 2021-01-25 5e4a0cdde3 [dev.regabi] all: merge master (bf0f7c9) into dev.regabi
+ 2021-01-25 bf0f7c9d78 doc/go1.16: mention os.DirFS in os section
+ 2021-01-25 deaf29a8a8 cmd/compile: fix order-of-assignment issue w/ defers
+ 2021-01-25 ad2ca26a52 doc/go1.16: mention os.DirEntry and types moved from os to io/fs
+ 2021-01-25 a51921fa5b doc/go1.16: mention new testing/iotest functions
+ 2021-01-25 e6b6d107f7 doc/go1.16: mention deprecation of io/ioutil
+ 2021-01-25 7eaaf28cae [dev.regabi] cmd/compile: disallow taking address of SSA'd values
+ 2021-01-25 96a276363b doc/go1.16: mention go/build changes
+ 2021-01-25 3d85c69a0b html/template: revert "avoid race when escaping updates template"
+ 2021-01-25 54514c6b28 cmd/go: fix TestScript/cgo_path, cgo_path_space when CC set
+ 2021-01-25 6f5e79f470 [dev.regabi] cmd/compile/internal: specify memory layout
+ 2021-01-25 cabffc199d [dev.regabi] cmd/compile/internal: add internal ABI specification
+ 2021-01-25 6de8443f3b doc/asm: add a section on go_asm.h, clean up go_tls.h section
+ 2021-01-25 6a4739ccc5 [dev.regabi] cmd/compile: enable rational constant arithmetic
+ 2021-01-25 be9612a832 [dev.regabi] os: disable TestDirFS until #42637 is fixed
+ 2021-01-25 8ee3d39838 [dev.regabi] cmd/go: workaround -race issue on ppc64le
+ 2021-01-25 54b251f542 lib/time, time/tzdata: update tzdata to 2021a
+ 2021-01-25 5a76c3d548 [dev.regabi] cmd/compile: modify abiutils for recently updated ABI
+ 2021-01-25 ff82cc971a os: force consistent mtime before running fstest on directory on Windows
+ 2021-01-25 044f937a73 doc/go1.16: fix WalkDir and Walk links
+ 2021-01-23 b634f5d97a doc/go1.16: add crypto/x509 memory optimization
+ 2021-01-23 9897655c61 doc/go1.16: reword ambiguously parsable sentence
+ 2021-01-23 cd99385ff4 cmd/internal/obj/arm64: fix VMOVQ instruction encoding error
+ 2021-01-23 66ee8b158f runtime: restore cgo_import_dynamic for libc.so on openbsd
+ 2021-01-22 25c39e4fb5 io/ioutil: fix example test for WriteFile to allow it to run in the playground
+ 2021-01-22 eb21b31e48 runtime: define dummy msanmove
+ 2021-01-22 3a778ff50f runtime: check for g0 stack last in signal handler
+ 2021-01-22 a2cef9b544 cmd/go: don't lookup the path for CC when invoking cgo

Change-Id: Iede4f98ba5ddbee2e16075d20186f8a9c095e378

src/cmd/compile/internal/noder/noder.go

@@ -1463,14 +1463,6 @@ func (p *noder) basicLit(lit *syntax.BasicLit) constant.Value {
 		p.errorAt(lit.Pos(), "malformed constant: %s", lit.Value)
 	}
 
-	// go/constant uses big.Rat by default, which is more precise, but
-	// causes toolstash -cmp and some tests to fail. For now, convert
-	// to big.Float to match cmd/compile's historical precision.
-	// TODO(mdempsky): Remove.
-	if v.Kind() == constant.Float {
-		v = constant.Make(ir.BigFloat(v))
-	}
-
 	return v
 }