java/openjdk{8,11}: Remove dependency on devel/llvm12 which is no longer necessary

The workarounds committed in aa1ca89826b5 and 846ff4e95291 are no longer
necessary, as both the upstream commits for PR258954
(https://github.com/battleblow/jdk11u/commit/305a68a90c722aa7a7b75589e24d5b5d554c96c1)
and PR264065 (https://hg.openjdk.java.net/jdk/jdk/rev/40c07de877ab) are
now merged into the distribution tarballs.

PR: 258954, 264065
Approved by: maintainer timeout (1 month)
MFH: 2022Q3