KT-50033 Add missing public API packages to module-info and setup a test

The test checks that new packages are not accidentally non-exported,
so each new stdlib package must be either exported or specified in that
test's expected non-exported package list.

libraries/stdlib/jdk8/java9/module-info.java

@@ -3,9 +3,11 @@ module kotlin.stdlib.jdk8 {
     requires transitive kotlin.stdlib;
     requires kotlin.stdlib.jdk7;
 
+    exports kotlin.jvm.jdk8;
     exports kotlin.collections.jdk8;
     exports kotlin.streams.jdk8;
     exports kotlin.text.jdk8;
+    exports kotlin.time.jdk8;
 
     opens kotlin.internal.jdk8 to kotlin.stdlib;
 }