FIR: Make 'suspend fun', where 'suspend' is not builtin error in 1.8

#KT-49264

compiler/testData/diagnostics/testsWithStdLib/coroutines/nonModifierFormForBuiltInWithFun.fir.kt

@@ -1,29 +0,0 @@
-// SKIP_TXT
-
-infix fun Int.suspend(c: () -> Unit) { c() }
-
-fun bar() {
-    1 <!MODIFIER_FORM_FOR_NON_BUILT_IN_SUSPEND!>suspend<!> fun() {
-        println()
-    }
-
-    1 <!SYNTAX!>@Ann suspend fun()<!> {
-        println()
-    }
-
-    1 <!MODIFIER_FORM_FOR_NON_BUILT_IN_SUSPEND!>suspend<!> @Ann fun() {
-        println()
-    }
-}
-
-@Target(AnnotationTarget.EXPRESSION)
-@Retention(AnnotationRetention.SOURCE)
-annotation class Ann
-
-fun main(suspend: WLambdaInvoke) {
-    1 <!MODIFIER_FORM_FOR_NON_BUILT_IN_SUSPEND!>suspend<!> fun() {}
-}
-
-class WLambdaInvoke {
-    operator fun Int.invoke(l: () -> Unit) {}
-}

compiler/testData/diagnostics/testsWithStdLib/coroutines/nonModifierFormForBuiltInWithFun.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // SKIP_TXT
 
 infix fun Int.suspend(c: () -> Unit) { c() }