versioner: ignore functions that are __INTRODUCED_IN_FUTURE.

Bug: http://b/28178111
Change-Id: I8026181e08ed8f2d59b31a37adcf8b469fb6bdaf
diff --git a/tools/versioner/tests/future/headers/foo.h b/tools/versioner/tests/future/headers/foo.h
new file mode 100644
index 0000000..b5113f4
--- /dev/null
+++ b/tools/versioner/tests/future/headers/foo.h
@@ -0,0 +1 @@
+int foo() __attribute__((availability(android, introduced = 10000)));