Move the rest of the tests to scons

tests/extra_fields/SConscript

@@ -0,0 +1,10 @@
+# Test that the decoder properly handles unknown fields in the input.
+
+Import("env")
+
+dec = env.GetBuildPath('#basic_buffer/${PROGPREFIX}decode_buffer${PROGSUFFIX}')
+env.RunTest('person_with_extra_field.output', [dec, "person_with_extra_field.pb"])
+env.Compare(["person_with_extra_field.output", "person_with_extra_field.expected"])
+
+dec2 = env.GetBuildPath('#alltypes/${PROGPREFIX}decode_alltypes${PROGSUFFIX}')
+env.RunTest('alltypes_with_extra_fields.output', [dec2, 'alltypes_with_extra_fields.pb'])