Fix var migration of variables initialized by static methods

[MBoegers]

What's changed?

Disables migration to var for variables initilized by static methods.

What's your motivation?

• (Hot) Fix Skip var replacement when the type cannot fully be resolved #608

Have you considered any alternatives or workarounds?

Skipping only those that are initialized by static generic Methods, but they are not sufficient identifiable.

Any additional context

I'll recheck with the JLS and my contacts, afterward I may file a follow-up bug.

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've used the IntelliJ IDEA auto-formatter on affected files

[timtebeek]

Thanks for the quick work here!