ci: use bitcoin-node for one depends job

The bitcoin-node binary is built on all platforms which have
multiprocess enabled, but for functional tests it's only used in
CentOS native (depends) job. The next commit will also add a
non-depends job.

ci/test/00_setup_env_native_centos.sh

@@ -18,3 +18,4 @@ export BITCOIN_CONFIG="\
  -DREDUCE_EXPORTS=ON \
  -DCMAKE_BUILD_TYPE=Debug \
 "
+export BITCOIN_CMD="bitcoin -m" # Used in functional tests