[FIR] Set implicit type for delegated constructor calls in fir builder

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/declarations/emptyAnonymousObject.txt

@@ -0,0 +1,10 @@
+FILE: emptyAnonymousObject.kt
+    public? final? fun test(): R|kotlin/Unit| {
+        lval x: <implicit> = object : R|kotlin/Any| {
+            private constructor(): R|anonymous| {
+                super<R|kotlin/Any|>()
+            }
+
+        }
+
+    }