compaction: LCS: kill unused bootstrapping code
compaction: LCS: kill unused bootstrapping code

With off-strategy, we no longer need LCS explicitly switching to STCS
mode, and even without off-strategy, the dynamic fan-in approach
in compaction manager will cause LCS to automatically switch to
STCS under heavy write load.

Signed-off-by: Raphael S. Carvalho <1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@scylladb.com>
Message-Id: <20220411181322.192830-1-1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@scylladb.com>

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