strings, bytes: Remove unnecessary function literals

[johanbrandhorst]

What version of Go are you using (go version)?

tip

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

linux/amd64

What did you do?

@quasilyte ran unlambda on the source tree and found the following instances of unnecessary function literals:

$GOROOT/src/hash/fnv/fnv_test.go:114:11: unlambda: replace `func() hash.Hash { return New128() }` with `New128`
$GOROOT/src/hash/fnv/fnv_test.go:115:12: unlambda: replace `func() hash.Hash { return New128a() }` with `New128a`
$GOROOT/src/strings/strings.go:621:13: unlambda: replace `func(r rune) rune { return c.ToUpper(r) }` with `c.ToUpper`
$GOROOT/src/strings/strings.go:627:13: unlambda: replace `func(r rune) rune { return c.ToLower(r) }` with `c.ToLower`
$GOROOT/src/strings/strings.go:633:13: unlambda: replace `func(r rune) rune { return c.ToTitle(r) }` with `c.ToTitle`
$GOROOT/src/bytes/bytes.go:492:13: unlambda: replace `func(r rune) rune { return c.ToUpper(r) }` with `c.ToUpper`
$GOROOT/src/bytes/bytes.go:498:13: unlambda: replace `func(r rune) rune { return c.ToLower(r) }` with `c.ToLower`
$GOROOT/src/bytes/bytes.go:504:13: unlambda: replace `func(r rune) rune { return c.ToTitle(r) }` with `c.ToTitle`

I intend to submit a CL to fix these.

[gopherbot]

Change https://golang.org/cl/127756 mentions this issue: hash/fnv, strings, bytes: avoid unnecessary function literals