schema CHANGE hide schema compilation behing lys_parse_mem()

Call lys_compile() automatically when the schema is being inserted into
the context to avoid requirement on user to call it separately.
diff --git a/tests/src/test_tree_schema_helpers.c b/tests/src/test_tree_schema_helpers.c
index 1c5ca3d..c3b3e50 100644
--- a/tests/src/test_tree_schema_helpers.c
+++ b/tests/src/test_tree_schema_helpers.c
@@ -17,6 +17,7 @@
 #include "../../src/set.c"
 #include "../../src/parser_yang.c"
 #include "../../src/tree_schema.c"
+#include "../../src/tree_schema_compile.c"
 #include "../../src/tree_schema_free.c"
 #include "../../src/tree_schema_helpers.c"
 #include "../../src/hash_table.c"