java 1.0 portgroup: remove java.enforce option

[chrstphrchvz]

Closes: https://trac.macports.org/ticket/68449

Description

Reasons for removal:

• It would be better for ports to never hardcode JDK paths in build outputs.
• java.enforce does not actually force a port to build using java.fallback, because it does not force JAVA_HOME to point to java.fallback rather than some other Java installation.
• This option is no longer used by any ports (it was only briefly used by abcl).

Verification

Have you

• followed our Commit Message Guidelines?
• squashed and minimized your commits?
• checked that there aren't other open pull requests for the same change?
• referenced existing tickets on Trac with full URL?

[mascguy]

When changing things done by others, we should be sure to tag them for review/comment.

Specifically, Kirill should have an opportunity to elaborate on the change, and/or veto it.

CC: @catap

[chrstphrchvz]

I could have been more conscientious about this by just mentioning it on the original PR.

I would also like to ask @breun for any feedback on this.

[breun]

@chrstphrchvz Fine with me. (I didn’t know of this flag and I’ve never used it.)

[mascguy]

@catap Kirill, thoughts on this?

[catap]

Sorry. Missed that. Feel free to remove it

[mascguy]

Sorry. Missed that. Feel free to remove it

Sounds good, thanks for confirming Kirill!

[catap]

Seems that the issue which I've tried to fix via this option still here: https://trac.macports.org/ticket/68804

:(