Support tofino build for P4_14 test programs

Also, modified programs such that both the P4_14 and P4_16 versions
produce the same forwarding behaviour and control API (i.e. P4Info)

Change-Id: I90b7fdfedff5f2a89e0f2295d32e2bb61cd0e0eb
diff --git a/tools/test/p4src/p4-16/include/actions.p4 b/tools/test/p4src/p4-16/include/actions.p4
index c9f2dec..0b87ef3 100644
--- a/tools/test/p4src/p4-16/include/actions.p4
+++ b/tools/test/p4src/p4-16/include/actions.p4
@@ -27,7 +27,7 @@
     standard_metadata.egress_spec = port;
 }
 
-action drop(inout standard_metadata_t standard_metadata) {
+action _drop(inout standard_metadata_t standard_metadata) {
     standard_metadata.egress_spec = DROP_PORT;
 }