Revert "Added API to set ephemeral port allocator range."

[akerouanton]

- What I did

Since commit 2c4a868, Docker doesn't
use the value of net.ipv4.ip_local_port_range when choosing an ephemeral
port. This change reverts back to the previous behavior.

Fixes #43054.

- How to verify it

1. make shell
2. In the container, sysctl -w net.ipv4.ip_local_port_range="39000 40000"
3. Start dockerd
4. Run docker run --rm -it -p 80 nginx
5. Check what port Docker has picked with docker ps

- Description for the changelog

Use the value of net.ipv4.ip_local_port_range when choosing an ephemeral port

[neersighted]

This looks really clean from a revert/application standpoint. However, I do wonder if it is desirable to reintroduce the ability to set the range over the API in a way that is documented and falls back to the kernel parameter as a default?

Regardless, this is aligned with the documented behavior and the right move given this has manifested as a regression for users.

[tianon]

I was worried that the removal of OptionDynamicPortRange would be a problem, but it looks like it was only ever used in #40055 (which is still unmerged). 👍

[tianon]

(This needs a rebase for some conflicts, but they look like they're pretty minor -- just the imports, perhaps?)

[thaJeztah]

Looks like these consts aren't used outside of the package, so I guess we can keep those

[thaJeztah]

Doing a quick rebase, and I'll add a commit to keep the consts un-exported

[thaJeztah]

LGTM

[akerouanton]

Ah, sorry @thaJeztah, didn't had time to rebase it today. Thanks for doing it 🙂

[thaJeztah]

No worries! (apologies on our side for this have taken so long!)

[thaJeztah]

Let me comment on this line; this may have been related to #40055 (comment) as well (in case we need to un-revert this change in range)

/cc @neersighted @corhere @evol262

(and myself, for if this causes havoc in our products 🙈)

[thaJeztah]

Failure is unrelated; known flaky test (#38521)

=== FAIL: github.com/docker/docker/integration-cli TestDockerSuite/TestStartReturnCorrectExitCode (4.54s)
    docker_cli_start_test.go:191: assertion failed: 
        Command:  D:\a\moby\moby\out\docker.exe start -a withRestart
        ExitCode: 0
        Stdout:   
        Stderr:   
        
        Failures:
        ExitCode was 0 expected 11
    --- FAIL: TestDockerSuite/TestStartReturnCorrectExitCode (4.54s)