Make zombienet tests native friendly (#6588)

* Make zombienet tests native friendly

* Update zombienet_tests/README.md

Co-authored-by: Bastian Köcher <info@kchr.de>

* Get rid of `{{ZOMBIENET_NATIVE_BINARY_PREFIX}}`

* Remove pointless changes

* add set_env helper and doc in readme

* changes from feedback

---------

Co-authored-by: Bastian Köcher <info@kchr.de>
Co-authored-by: Javier Viola <javier@parity.io>

polkadot/zombienet_tests/smoke/0001-parachains-smoke-test.toml

@@ -21,7 +21,7 @@ addToGenesis = false
   [parachains.collator]
   name = "collator01"
   image = "{{COL_IMAGE}}"
-  command = "/usr/local/bin/adder-collator"
+  command = "adder-collator"
   args = [ "-lruntime=debug,parachain=trace" ]
 
 [types.Header]

polkadot/zombienet_tests/smoke/0003-deregister-register-validator-smoke.toml

@@ -21,4 +21,3 @@ command = "polkadot"
   [[relaychain.nodes]]
   name = "dave"
   args = [ "-lruntime=debug,parachain=trace" ]
-