[MONSTOR-14833] Mimic real key prefix pattern for Jungle bench

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key samples:

idx: 88540 key mrnfzfl|sozr|aaaafazk
idx: 18106 key cdbcbvg|zpv|aaaabauk
idx: 128277 key lmcnzba|fzhk|aaaahhttsgn
idx: 171707 key ekaoyzhg|ozuy|aaaajuadjq
idx: 185748 key uusrjwzip|zfco|aaaakoue
idx: 61792 key nvgthpntn|dwv|aaaadnkqcr
idx: 29337 key gcjzqesvz|bmm|aaaabrkjesj
idx: 15945 key xwjtnrlmj|kejh|aaaaaxph
idx: 12252 key oixcpwd|vgai|aaaaasdgdar
idx: 123240 key slnhrzbhf|wtf|aaaahaia
idx: 147316 key rvghbzicx|xjp|aaaaijyaif
idx: 135306 key fkjvkbhln|zhn|aaaahsechny
idx: 139222 key ijqnwfe|phv|aaaahxys
idx: 5471 key kgbmtljlq|wtx|aaaaaicl
idx: 184753 key vneelre|irsb|aaaaknhx
idx: 5464 key ijwkgw|gwgp|aaaaaice
idx: 150732 key pojfvb|khg|aaaaiozk

[greensky00]

Please use a 4-space indent, also seems to me fanout is not implemented.

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support fanout level 1: gvrgogxs gjhamyayz level 2: xtps piu fhv

index 55841 gvrgogxs|xtps|aaaadeptkr
index 119269 gvrgogxs|piu|aaaagulh
index 132311 gvrgogxs|xtps|aaaahnsx
index 94337 gvrgogxs|xtps|aaaafjoje
index 166719 gvrgogxs|fhv|aaaajmqhozk
index 125504 gjhamyayz|xtps|aaaahdrcuw
index 137118 gjhamyayz|fhv|aaaahuvu
index 171321 gvrgogxs|fhv|aaaajtlhsb
index 16798 gjhamyayz|piu|aaaaaywcr
index 176426 gjhamyayz|xtps|aaaakazq
index 122181 gvrgogxs|fhv|aaaagyth
index 128009 gvrgogxs|xtps|aaaahhjl
index 90579 gvrgogxs|fhv|aaaafdzv
index 108578 gjhamyayz|xtps|aaaageqcvxo
index 139419 gvrgogxs|fhv|aaaahyghb
index 100804 gjhamyayz|piu|aaaaftdc