Refactor StaticInnerClassCleanUp to jdt.core.manipulation

[jjohnstn]

• move StaticInnerClassCleanUp to StaticInnerClassCleanUpCore in jdt.core.manipulation
• fixes #1492

What it does

See title.

How to test

Run the jdt.ui cleanup tests.

Author checklist

• [x] I have thoroughly tested my changes
• [x] The change is following the coding conventions
• [x] I have signed the Eclipse Contributor Agreement (ECA)

[jjohnstn]

Test failures are due to some compiler changes regarding sealed classes that aren't in I-builds yet.