FIR: report UNSAFE_CALL on dot when possible

compiler/testData/diagnostics/testsWithStdLib/coroutines/kt36947.fir.kt

@@ -1,6 +0,0 @@
-val foo = iterator {
-    yield(0)
-    val nullable: String? = null
-    nullable.<!UNSAFE_CALL!>length<!>
-    nullable.<!UNSAFE_CALL!>get<!>(2)
-}

compiler/testData/diagnostics/testsWithStdLib/coroutines/kt36947.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 val foo = iterator {
     yield(0)
     val nullable: String? = null

compiler/testData/diagnostics/testsWithStdLib/coroutines/restrictSuspension/outerYield_1_3.fir.kt

@@ -87,7 +87,7 @@ fun test() {
                 this@with.<!UNRESOLVED_REFERENCE!>yield<!>("")
 
                 yield2("")
-                this@with.<!UNSAFE_CALL!>yield2<!>("")
+                this@with<!UNSAFE_CALL!>.<!>yield2("")
             }
         }
     }