boot_strapper: Ignore node to be replaced explicitly as stream source
boot_strapper: Ignore node to be replaced explicitly as stream source

After commit 7d86a3b208659e92489216e71df13fb33b1a4c3a (storage_service:
Make replacing node take writes), during replace operation, tokens in
_token_metadata for node being replaced are updated only after the replace
operation is finished. As a result, in range_streamer::add_ranges, the
node being replaced will be considered as a source to stream data from.

Before commit 7d86a3b208659e92489216e71df13fb33b1a4c3a, the node being
replaced will not be considered as a source node because it is already
replaced by the replacing node before the replace operation is finished.
This is the reason why it works in the past.

To fix, filter out the node being replaced as a source node explicitly.

Tests: replace_first_boot_test and replace_stopped_node_test
Backports: 4.1
Fixes: #6728

scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla