added tests for KT-2369, KT-2585 and KT-2972

KT-2369 Variable is not marked as uninitialized in 'finally' section
 #KT-2369 fixed
KT-2585 Code in try-finally is incorrectly marked as unreachable
 #KT-2585 fixed
KT-2972 Wrong "unused value" warning when finally is present
 #KT-2972 fixed

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt2369.kt

@@ -0,0 +1,13 @@
+//KT-2369 Variable is not marked as uninitialized in 'finally' section
+
+fun main(args: Array<String>) {
+    var x : Int
+    try {
+        throw Exception()
+    }
+    finally {
+        doSmth(<!UNINITIALIZED_VARIABLE!>x<!> + 1)
+    }
+}
+
+fun doSmth(a: Any?) = a