New poison for Java gencode and MSVC+Bazel combination

[David Castro]

Poison Java gencode

We are patching a change into the 25.x branch that will poison Java gencode that was created prior to the 3.21.7 release. We will then mark all versions of Java protobuf from 3.21.7 through 3.25.5 as vulnerable to the footmitten CVE.

Poison MSVC + Bazel

We will be dropping support for using Bazel and MSVC together in v34. As of v30, we will poison this combination with an error unless you specify the opt-out flag --define=protobuf_allow_msvc=true to silence it.

For more details on these changes, see the corresponding news article.