FIR CFG: check lambda concurrency by data flow, not control flow

var p: String? = something
    if (p != null) {
      foo(
        run { p = null; n() },
        // This lambda executes strictly after the one above by CFG,
        // but data flow for type inference comes from before the call
        // so p would get smartcasted if not forbidden.
	run { p.length; 123 }
      )
    }

compiler/fir/analysis-tests/testData/resolve/cfg/flowFromTwoInplaceLambdas.kt

@@ -23,6 +23,17 @@ fun test1(x: String?) {
     }
 }
 
+fun test1_tail(x: String?) {
+    var p = x
+    if (p != null) {
+        run2({ p = null; n() }) {
+            <!SMARTCAST_IMPOSSIBLE!>p<!>.length // Bad: may or may not not be called first
+            123
+        }
+        p<!UNSAFE_CALL!>.<!>length // Bad: p = null
+    }
+}
+
 fun test2(x: Any?) {
     var p: Any? = x
     p.<!UNRESOLVED_REFERENCE!>length<!> // Bad