Add some tests for #if compiler

Author: danielmartin

test/Parse/ConditionalCompilation/compiler.swift

@@ -0,0 +1,29 @@
+// RUN: %target-typecheck-verify-swift
+
+#if !compiler(>=4.1)
+ // There should be no error here.
+ foo bar
+#else
+ let _: Int = 1
+#endif
+
+#if compiler(<4.1)
+ // There should be no error here.
+ foo bar
+#else
+ let _: Int = 1
+#endif
+
+#if (compiler(>=4.1))
+ let _: Int = 1
+#else
+ // There should be no error here.
+ foo bar
+#endif
+
+#if !compiler(<4.1)
+ let _: Int = 1
+#else
+ // There should be no error here.
+ foo bar
+#endif