Mark expressions for correct recognition by "unreachable code"

compiler/testData/diagnostics/tests/controlFlowAnalysis/unreachableCode.kt

@@ -0,0 +1,55 @@
+fun foo(<!UNUSED_PARAMETER!>a<!>: Any) {}
+fun bar(<!UNUSED_PARAMETER!>a<!>: Any, <!UNUSED_PARAMETER!>b<!>: Any) {}
+
+fun test(arr: Array<Int>) {
+    while (true) {
+        <!UNREACHABLE_CODE!>foo<!>(break)
+    }
+
+
+    while (true) {
+        <!UNREACHABLE_CODE!>bar<!>(arr, break)
+    }
+
+    while (true) {
+        <!UNREACHABLE_CODE!>arr[break]<!>
+    }
+
+    while (true) {
+        <!UNREACHABLE_CODE!>arr[1]<!> = break
+    }
+
+    while (true) {
+        break
+        <!UNREACHABLE_CODE!>foo(1)<!>
+    }
+
+    while (true) {
+        var <!UNUSED_VARIABLE!>x<!> = 1
+        break
+        <!UNREACHABLE_CODE!>x = 2<!>
+    }
+
+    while (true) {
+        var <!UNUSED_VARIABLE!>x<!> = 1
+        <!UNREACHABLE_CODE!>x = break<!>
+    }
+
+    // TODO: bug, should be fixed in CFA
+    while (true) {
+        if (1 > 2 && break && 2 > 3) {
+
+        }
+    }
+
+    // TODO: bug, should be fixed in CFA
+    while (true) {
+        if (1 > 2 || break || 2 > 3) {
+
+        }
+    }
+
+    while (true) {
+        <!USELESS_ELVIS!>break<!> ?: <!UNREACHABLE_CODE!>null<!>
+    }
+}