[FIR] Make reporting of local class diagnostics more consistent with K1

It would be nice to report more appropriate diagnostics at the
corresponding places, but right now it's more important to
fix greenness-redness problems. Plus, this is already how K1 works.

^KT-59900 Fixed

compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv12.fir.kt

@@ -6,7 +6,7 @@ enum class Enum {
 
         <!NESTED_CLASS_NOT_ALLOWED!>class TestNested<!>
 
-        <!LOCAL_INTERFACE_NOT_ALLOWED, NESTED_CLASS_NOT_ALLOWED!>interface TestInterface<!>
+        <!NESTED_CLASS_NOT_ALLOWED!>interface TestInterface<!>
 
         <!LOCAL_OBJECT_NOT_ALLOWED!>object TestObject<!>
 

compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv13.fir.kt

@@ -6,7 +6,7 @@ enum class Enum {
 
         <!NESTED_CLASS_NOT_ALLOWED!>class TestNested<!>
 
-        <!LOCAL_INTERFACE_NOT_ALLOWED, NESTED_CLASS_NOT_ALLOWED!>interface TestInterface<!>
+        <!NESTED_CLASS_NOT_ALLOWED!>interface TestInterface<!>
 
         <!LOCAL_OBJECT_NOT_ALLOWED!>object TestObject<!>
 

compiler/testData/diagnostics/tests/inner/kt6026.fir.kt

@@ -1,8 +0,0 @@
-// KT-6026 Exception on instantiating a nested class in an anonymous object
-
-val oo = object {
-    // Forbidden in KT-13510
-    class Nested
-
-    fun f1() = Nested(<!TOO_MANY_ARGUMENTS!>11<!>)
-}

compiler/testData/diagnostics/tests/inner/kt6026.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // KT-6026 Exception on instantiating a nested class in an anonymous object
 
 val oo = object {