Align definePackage behavior with JRE modular classloaders

[shartte]

This is an obvious breaking change

SJH will currently "manually" definePackage every package it comes across. The revised Javadoc for definePackage says this is discouraged, and the JRE itself does not do this.

This leads to a discrepancy between SJH and platform modular loaders which prevents us from using them, currently. (As a consequence we cannot put FML or ML directly onto the JRE module path).

A version of SJH with this change will no longer return the implementation version and specification version of packages, and calls to Package#isCompatibleWith will not work.

[marchermans]

Do we know why this is discouraged by the JDK?

[shartte]

Do we know why this is discouraged by the JDK?

Nope. Probably because they define the package implicitly anyway in modular loaders.

p.s.: A side-effect is that the fix to load package-info is no longer needed since it'll be implicitly loaded by the package definition that results from defining a class in that package (fun!)

[Matyrobbrt]

Was the use of the package in fabric mixin fixed?

[shartte]

Fabric Mixin released a new version that contains this change:
0.14.0+mixin.0.8.6