all: use strings.ReplaceAll where applicable

```
find . \
-not -path './.git/*' \
-not -path './test/*' \
-not -path './src/cmd/vendor/*' \
-not -wholename './src/strings/example_test.go' \
-type f \
-exec \
sed -i -E 's/strings\.Replace\((.+), -1\)/strings\.ReplaceAll\(\1\)/g' {} \;
```

Change-Id: I59e2e91b3654c41a32f17dd91ec56f250198f0d6
GitHub-Last-Rev: 0868b1eccc
GitHub-Pull-Request: golang/go#73370
Reviewed-on: https://go-review.googlesource.com/c/go/+/665395
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Robert Griesemer <gri@google.com>

src/cmd/cgo/gcc.go

@@ -2863,7 +2863,7 @@ func (c *typeConv) loadType(dtype dwarf.Type, pos token.Pos, parent string) *Typ
 			if ss, ok := dwarfToName[s]; ok {
 				s = ss
 			}
-			s = strings.Replace(s, " ", "", -1)
+			s = strings.ReplaceAll(s, " ", "")
 			name := c.Ident("_Ctype_" + s)
 			tt := *t
 			typedef[name.Name] = &tt