Fix invalid sync request

[arvidn]

Purpose:

When exposed to a heavier peak with a lower height than our current peak, we currently fall into the short-sync (catch-up) case because the current logic (mistakenly) assumes the heavier peak has a greater height. This results in us sending an invalid block request to the peer, which in turn responds with a None message.

The log looks like this:

11:52:23 chia.full_node.full_node: INFO Starting batch short sync from 1593 to height 1077
11:52:23 chia.full_node.full_node: ERROR Error short batch syncing, could not fetch block at height 1593

In the above test our (lighter) peak height is 1593 and the other (heavier) peak height is 1077. We end up requesting block 1593 from the peer.

This patch adds the additional condition that the heavier peak also has a greater or equal height, as it appears was the intention to begin with. This avoids sending an invalid block request to the peer and we immediately fall back to a long sync.

Current Behavior:

We send an invalid request, handle the resulting error and then initiate the long sync.

New Behavior:

We initiate the long sync right away.

[github-actions]

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[github-actions]

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[github-actions]

Conflicts have been resolved. A maintainer will review the pull request shortly.

[coveralls-official]

Pull Request Test Coverage Report for Build 6787966429

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• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• 26 unchanged lines in 7 files lost coverage.
• Overall coverage decreased (-0.02%) to 90.284%

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Files with Coverage Reduction	New Missed Lines	%
chia/introducer/introducer.py	1	78.02%
chia/server/server.py	1	81.45%
chia/wallet/util/wallet_sync_utils.py	1	77.21%
chia/server/node_discovery.py	2	79.55%
chia/full_node/full_node.py	5	84.39%
chia/farmer/farmer.py	7	66.44%
chia/wallet/wallet_node.py	9	86.83%

Totals
Change from base Build 6787911924:	-0.02%
Covered Lines:	93075
Relevant Lines:	103039

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💛 - Coveralls

[wjblanke]

aok