analyze object when selecting from package (#21511)

This PR is an updated version of #20424, which fixes a bug in the global
initialization checker such that when accessing global object through
full path, the checker immediately analyzes the initialization code of
the corresponding object.

[test_scala2_library_tasty]

compiler/src/dotty/tools/dotc/transform/init/Objects.scala

@@ -867,7 +867,7 @@ class Objects(using Context @constructorOnly):
       Bottom
 
     case Bottom =>
-      if field.isStaticObject then ObjectRef(field.moduleClass.asClass)
+      if field.isStaticObject then accessObject(field.moduleClass.asClass)
       else Bottom
 
     case ValueSet(values) =>

compiler/test/dotc/neg-init-global-scala2-library-tasty.blacklist

@@ -5,3 +5,16 @@ unapplySeq-implicit-arg.scala
 unapplySeq-implicit-arg2.scala
 unapplySeq-implicit-arg3.scala
 ScalaCheck.scala
+mutable-read8.scala
+TypeCast.scala
+global-cycle8.scala
+global-cycle6.scala
+i12544b.scala
+t9360.scala
+mutable-array.scala
+patmat-unapplySeq2.scala
+line-spacing.scala
+global-list.scala
+t5366.scala
+mutable-read7.scala
+t9115.scala

tests/init-global/warn/cyclic-object.scala

@@ -0,0 +1,9 @@
+package cyclicObject
+
+object O1 { // warn
+  val o = cyclicObject.O2
+}
+
+object O2 {
+  val o = cyclicObject.O1
+}