Psi: Introduce KtScriptInitializer, a separate entity for script initializers which are quite a bit different from class initializers

idea/testData/stubs/NotStorePropertiesFrom.expected

@@ -6,6 +6,6 @@ PsiJetFileStubImpl[package=]
       VALUE_PARAMETER_LIST:
     CLASS_BODY:
       PROPERTY:[fqName=Test.test, hasDelegate=false, hasDelegateExpression=false, hasInitializer=true, hasReturnTypeRef=false, isExtension=false, isTopLevel=false, isVar=false, name=test]
-      ANONYMOUS_INITIALIZER:
+      CLASS_INITIALIZER:
       FUN:[fqName=Test.more, hasBlockBody=true, hasBody=true, hasTypeParameterListBeforeFunctionName=false, isExtension=false, isTopLevel=false, name=more]
         VALUE_PARAMETER_LIST:

idea/testData/stubs/SecondaryConstructors.expected

@@ -10,7 +10,7 @@ PsiJetFileStubImpl[package=test]
             USER_TYPE:[isAbsoluteInRootPackage=false]
               REFERENCE_EXPRESSION:[referencedName=Boolean]
     CLASS_BODY:
-      ANONYMOUS_INITIALIZER:
+      CLASS_INITIALIZER:
       SECONDARY_CONSTRUCTOR:
         MODIFIER_LIST:[]
           ANNOTATION_ENTRY:[hasValueArguments=false, shortName=anno]
@@ -23,7 +23,7 @@ PsiJetFileStubImpl[package=test]
             TYPE_REFERENCE:
               USER_TYPE:[isAbsoluteInRootPackage=false]
                 REFERENCE_EXPRESSION:[referencedName=String]
-      ANONYMOUS_INITIALIZER:
+      CLASS_INITIALIZER:
       SECONDARY_CONSTRUCTOR:
         MODIFIER_LIST:[private]
         VALUE_PARAMETER_LIST: