Build java9 modular artifacts under 'modular' classifier

Provide additional modular artifacts as a workaround for KT-21266

Update module-info declarations:
  - add new packages
  - add exports and opens for internal PlatformImplementations
  - remove exports of kotlin.coroutines.experimental.*

#KT-27919 Fixed

libraries/commonConfiguration.gradle

@@ -90,13 +90,10 @@ ext.manifestAttributes = { Manifest manifest, Project project, String component
                 'Kotlin-Runtime-Component': component,
                 'Kotlin-Version': project.kotlinLanguageVersion
         }
-        // TODO: enable as soon as this doesn't cause D8/DX to crash
-        /*
         if (multiRelease) {
             attributes \
                 'Multi-Release': 'true'
         }
-        */
     }
 }