Extract util.runtime module out of util

Cleanup module dependencies: a lot of modules depended on 'frontend.java' just
to use something from 'util' module, exported by 'frontend.java', whereas they
really need nothing from 'frontend.java'. Also 'frontend.java' just exported
'util', not using anything from it.

Create a new 'util.runtime' module, which will be available at runtime. Make
'util' export 'util.runtime' and make all modules who needed these utils depend
on 'util' directly instead of 'frontend.java'

compiler/frontend.java/frontend.java.iml

@@ -9,7 +9,6 @@
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="module" module-name="frontend" />
     <orderEntry type="library" scope="PROVIDED" name="intellij-core" level="project" />
-    <orderEntry type="module" module-name="util" exported="" />
     <orderEntry type="module" module-name="runtime" />
     <orderEntry type="library" name="javax.inject" level="project" />
     <orderEntry type="module" module-name="serialization" />