Minor, remove extraneous box tests

These tests are already present in
`compiler/testData/codegen/box/classes/kt496.kt`.

compiler/testData/codegen/box/controlStructures/tryCatchInExpressions/splitTryCorner1.kt

@@ -1,11 +0,0 @@
-fun shouldReturnFalse() : Boolean {
-    try {
-        return true
-    } finally {
-        if (true)
-            return false
-    }
-}
-
-fun box(): String =
-        if (shouldReturnFalse()) "Failed" else "OK"

compiler/testData/codegen/box/controlStructures/tryCatchInExpressions/splitTryCorner2.kt

@@ -1,22 +0,0 @@
-fun shouldReturn11() : Int {
-    var x = 0
-    while (true) {
-        try {
-            if(x < 10)
-                x++
-            else
-                break
-        }
-        finally {
-            x++
-        }
-    }
-    return x
-}
-
-fun box(): String {
-    val test = shouldReturn11()
-    if (test != 11) return "Failed, test=$test"
-
-    return "OK"
-}