Mark only unreachable parts of element if it has reachable parts

like for 'return todo()' mark only 'return'

compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/commasAndWhitespaces.kt

@@ -0,0 +1,12 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun testCommasAndWhitespaces() {
+    fun bar(i: Int, s: String, x: Any) {}
+
+    <!UNREACHABLE_CODE!>bar(<!> 1 , todo() , <!UNREACHABLE_CODE!>"" )<!>
+}
+
+fun todo() = throw Exception()
+
+
+