Remove obsolete build tags

[alexbozhenko]

Run:
# go fix ./...

It removed obsolete // +build lines: https://tip.golang.org/doc/go1.18#go-build-lines
Current build tag syntax: https://pkg.go.dev/cmd/go#hdr-Build_constraints

Since new fixes are rarely introduced, we shouldn't bother with running this automatically:
https://go.dev/blog/introducing-gofix
https://pkg.go.dev/cmd/fix@go1.23.5

go tool fix -h
Available rewrites are:

buildtag
        Remove +build comments from modules using Go 1.18 or later

cftype
        Fixes initializers and casts of C.*Ref and JNI types

context
        Change imports of golang.org/x/net/context to context

egl
        Fixes initializers of EGLDisplay

eglconf
        Fixes initializers of EGLConfig

gotypes
        Change imports of golang.org/x/tools/go/{exact,types} to go/{constant,types}

jni
        Fixes initializers of JNI's jobject and subtypes

netipv6zone
        Adapt element key to IPAddr, UDPAddr or TCPAddr composite literals.

        https://codereview.appspot.com/6849045/

printerconfig
        Add element keys to Config composite literals.

Signed-off-by: Alex Bozhenko alex@synadia.com

[wallyqs]

LGTM