IR: annotations are represented as IrConstructorCall elements

Also, they are rendered somewhat nicer

compiler/testData/ir/irText/declarations/annotations/propertiesWithAnnotations.txt

@@ -29,8 +29,7 @@ FILE fqName:<root> fileName:/propertiesWithAnnotations.kt
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any 
   PROPERTY name:testVal visibility:public modality:FINAL [val] 
     annotations:
-      CALL 'public constructor <init> (x: kotlin.String) [primary] declared in <root>.TestAnn' type=<root>.TestAnn origin=null
-        x: CONST String type=kotlin.String value="testVal.property"
+      TestAnn(x = 'testVal.property')
     FIELD PROPERTY_BACKING_FIELD name:testVal type:kotlin.String visibility:public [final,static] 
       EXPRESSION_BODY
         CONST String type=kotlin.String value=""