analysis-stats: run Salsa's LRU at the end of analysis

[davidbarsky]

Should help with #18964 (comment) bit.

[lnicola]

I can't test it right now, does it reduce the memory usage as displayed?

[lnicola]

I don't think it does:

# baseline
Database loaded:     21.03s, 529minstr, 96mb (metadata 179.81ms, 5466kinstr, 972kb; build 20.51s, 13minstr, 46kb)
  item trees: 1289
Item Tree Collection: 691.76ms, 7589minstr, 126mb
  crates: 58, mods: 1140, decls: 29642, bodies: 28783, adts: 2045, consts: 1719
Item Collection:     10.29s, 83ginstr, 1487mb
Body lowering:       4.16s, 27ginstr, 641mb                                                                                                                                       
  exprs: 875276, ??ty: 66 (0%), ?ty: 131 (0%), !ty: 4                                                                                                                             
  pats: 192444, ??ty: 6 (0%), ?ty: 6 (0%), !ty: 0
Inference:           76.89s, 512ginstr, 1227mb
MIR lowering:        14.17s, 95ginstr, 451mb
Mir failed bodies: 45 (0%)
Data layouts:        73.56ms, 378minstr, 19mb
Failed data layouts: 0 (0%)
Const evaluation:    38.08ms, 234minstr, 4mb
Failed const evals: 3 (0%)
Total:               106.40s, 728ginstr, 3958mb

# pr
Database loaded:     667.81ms, 528minstr, 96mb (metadata 299.37ms, 5472kinstr, 972kb; build 165.04ms, 13minstr, 47kb)
  item trees: 1289
Item Tree Collection: 715.85ms, 7590minstr, 126mb
  crates: 58, mods: 1140, decls: 29642, bodies: 28783, adts: 2045, consts: 1719
Item Collection:     10.53s, 83ginstr, 1487mb
Body lowering:       4.18s, 27ginstr, 642mb                                                                                                                                       
  exprs: 875276, ??ty: 66 (0%), ?ty: 131 (0%), !ty: 4                                                                                                                             
  pats: 192444, ??ty: 6 (0%), ?ty: 6 (0%), !ty: 0
Inference:           79.91s, 531ginstr, 1227mb
MIR lowering:        14.10s, 97ginstr, 451mb
Mir failed bodies: 45 (0%)
Data layouts:        75.20ms, 378minstr, 19mb
Failed data layouts: 0 (0%)
Const evaluation:    39.37ms, 230minstr, 4mb
Failed const evals: 3 (0%)
Total:               109.64s, 748ginstr, 3959mb

[davidbarsky]

Fixed the incorrect placement of db.trigger_lru_eviction! That brought analysis-stats on Salsa from 1529mb to 937mb. On rust-analyzer (when run atop of #19359), the correct placement of db.trigger_lru_eviction brought analysis-stats from 4169mb to 2496mb.