[testsuite] Update TestREPLSubclassing to be an inline REPL test (#246)

This fixes pexpect-related test failures in CI and makes the test more predictable.
diff --git a/packages/Python/lldbsuite/test/repl/subclassing/TestREPLSubclassing.py b/packages/Python/lldbsuite/test/repl/subclassing/TestREPLSubclassing.py
index 5e92c88..caabfff 100644
--- a/packages/Python/lldbsuite/test/repl/subclassing/TestREPLSubclassing.py
+++ b/packages/Python/lldbsuite/test/repl/subclassing/TestREPLSubclassing.py
@@ -1,35 +1,4 @@
-# TestREPLSubclassing.py
-#
-# This source file is part of the Swift.org open source project
-#
-# Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
-# Licensed under Apache License v2.0 with Runtime Library Exception
-#
-# See https://swift.org/LICENSE.txt for license information
-# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-#
-# ------------------------------------------------------------------------------
-"""This test verifies that the REPL can validly do subclass."""
+import lldbsuite.test.lldbinrepl as lldbinrepl
+import lldbsuite.test.lldbtest as lldbtest
 
-import os
-import time
-import unittest2
-import lldb
-import lldbsuite.test.lldbrepl as lldbrepl
-from lldbsuite.test import decorators
-
-
-class REPLSubclassingTestCase (lldbrepl.REPLTest):
-
-    mydir = lldbrepl.REPLTest.compute_mydir(__file__)
-
-    def doTest(self):
-        self.command('class A {init(a: Int) {}}')
-        self.command(
-            'class B : A {let x: Int; init() { x = 5 + 5; super.init(a: x) } }')
-        self.command('print(B().x)', patterns=['10'])
-        self.command(
-            'extension B : CustomStringConvertible { public var description:String { return "class B\(x) is a subclass of class A"} }')
-        self.command(
-            'print(B())',
-            patterns=['class B(10) is a subclass of class A'])
+lldbinrepl.MakeREPLTest(__file__, globals(), [])
diff --git a/packages/Python/lldbsuite/test/repl/subclassing/input.swift b/packages/Python/lldbsuite/test/repl/subclassing/input.swift
new file mode 100644
index 0000000..398119b
--- /dev/null
+++ b/packages/Python/lldbsuite/test/repl/subclassing/input.swift
@@ -0,0 +1,22 @@
+// input.swift
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+// -----------------------------------------------------------------------------
+
+class A {init(a: Int) {}}
+///
+class B : A {let x: Int; init() { x = 5 + 5; super.init(a: x) } }
+///
+B().x
+///10
+extension B : CustomStringConvertible { public var description:String { return "class B\(x) is a subclass of class A"} }
+///
+B().description
+///class B10 is a subclass of class A
diff --git a/packages/Python/lldbsuite/test/repl/subclassing/main.swift b/packages/Python/lldbsuite/test/repl/subclassing/main.swift
new file mode 100644
index 0000000..57fc432
--- /dev/null
+++ b/packages/Python/lldbsuite/test/repl/subclassing/main.swift
@@ -0,0 +1,16 @@
+// main.swift
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2017 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+// -----------------------------------------------------------------------------
+
+func stop_here() {
+  // Set breakpoint here.
+}
+stop_here()