PHOENIX-7834 CDCBaseIT do not force-delete a never-upserted row

[apurtell]

CDCBaseIT.generateMutations has a second-half "force a delete if there was none so far" branch that flips isDelete=true without checking whether the candidate row was ever upserted in this run, so when random batch participation has skipped a key in every prior batch the forced DELETE lands on a non-existent row and produces an HBase tombstone with no matching put. The data table view sees no change, and a later legitimate upsert for the same key surfaces as the next CDC change event on a forView=true CDC while the expected change list still has the tombstone marked as a delete, tripping CDCBaseIT.verifyChangesViaSCN with ComparisonFailure expected:<delete> but was:<upsert> in CDCQueryIT.testSelectGeneric[forView=true, encodingScheme=TWO_BYTE_QUALIFIERS, multitenant=false, tableSaltBuckets=null, withSchemaName=false, caseSensitiveNames=false]. The fix gates the forced-delete branch on mutatedRows.contains(rows.get(j)) so a delete is only ever forced on a row that has already been upserted.