[FIR] Fix stackoverflow when checking for type cast erasure

#KT-59478 Fixed

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirCastDiagnosticsHelpers.kt

@@ -128,7 +128,7 @@ fun isCastErased(supertype: ConeKotlinType, subtype: ConeKotlinType, context: Ch
     }
 
     // cast between T and T? is always OK
-    if (supertype.isMarkedNullable || subtype.isMarkedNullable) {
+    if ((supertype !is ConeErrorType && supertype.isMarkedNullable) || (subtype !is ConeErrorType && subtype.isMarkedNullable)) {
         return isCastErased(
             supertype.withNullability(ConeNullability.NOT_NULL, typeContext),
             subtype.withNullability(ConeNullability.NOT_NULL, typeContext),

compiler/testData/diagnostics/tests/cast/bare/ToErrorType.fir.kt

@@ -3,4 +3,9 @@ class P
 fun foo(p: P): Any {
     val v = p as <!UNRESOLVED_REFERENCE!>G<!>
     return v
-}
+}
+
+fun bar(p: P): Any {
+    val v = p as <!UNRESOLVED_REFERENCE!>G<!>?
+    return v
+}

compiler/testData/diagnostics/tests/cast/bare/ToErrorType.kt

@@ -3,4 +3,9 @@ class P
 fun foo(p: P): Any {
     val v = p as <!UNRESOLVED_REFERENCE!>G<!>
     return <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>v<!>
-}
+}
+
+fun bar(p: P): Any {
+    val v = p as <!UNRESOLVED_REFERENCE!>G<!>?
+    return <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>v<!>
+}

compiler/testData/diagnostics/tests/cast/bare/ToErrorType.txt

@@ -1,5 +1,6 @@
 package
 
+public fun bar(/*0*/ p: P): kotlin.Any
 public fun foo(/*0*/ p: P): kotlin.Any
 
 public final class P {