K1: count anonymous function as function expression in checkers

Related to KT-57991

compiler/testData/diagnostics/tests/modifiers/suspendAnonymousFunction.fir.kt

@@ -1,7 +0,0 @@
-// ISSUE: KT-57991
-
-fun foo() {
-    <!WRONG_MODIFIER_TARGET!>suspend<!> fun() {
-
-    }
-}

compiler/testData/diagnostics/tests/modifiers/suspendAnonymousFunction.kt

@@ -1,7 +1,8 @@
+// FIR_IDENTICAL
 // ISSUE: KT-57991
 
 fun foo() {
-    suspend fun() {
+    <!WRONG_MODIFIER_TARGET!>suspend<!> fun() {
 
     }
 }