Cranelift: Use bump allocation in remove_constant_phis pass (#4710)

* Cranelift: Use bump allocation in `remove_constant_phis` pass

This makes compilation 2-6% faster for Sightglass's bz2 benchmark:

```
compilation :: cycles :: benchmarks/bz2/benchmark.wasm

  Δ = 7290648.36 ± 4245152.07 (confidence = 99%)

  bump.so is 1.02x to 1.06x faster than main.so!

  [166388177 183238542.98 214732518] bump.so
  [172836648 190529191.34 217514271] main.so

compilation :: cycles :: benchmarks/pulldown-cmark/benchmark.wasm

  No difference in performance.

  [182220055 225793551.12 277857575] bump.so
  [193212613 227784078.61 277175335] main.so

compilation :: cycles :: benchmarks/spidermonkey/benchmark.wasm

  No difference in performance.

  [3848442474 4295214144.37 4665127241] bump.so
  [3969505457 4262415290.10 4563869974] main.so
```

* Add audit for `bumpalo`

* Add an audit of `arrayvec` version 0.7.2

* Remove unnecessary `collect` into `Vec`

I wasn't able to measure any perf difference here, but its nice to do anyways.

* Use a `SecondaryMap` for keeping track of summaries

supply-chain/audits.toml

@@ -1,12 +1,27 @@
 
 # cargo-vet audits file
 
+[[audits.arrayvec]]
+who = "Nick Fitzgerald <fitzgen@gmail.com>"
+criteria = "safe-to-deploy"
+version = "0.7.2"
+notes = """
+Well documented invariants, good assertions for those invariants in unsafe code,
+and tested with MIRI to boot. LGTM.
+"""
+
 [[audits.backtrace]]
 who = "Alex Crichton <alex@alexcrichton.com>"
 criteria = "safe-to-deploy"
 version = "0.3.66"
 notes = "I am the author of this crate."
 
+[[audits.bumpalo]]
+who = "Nick Fitzgerald <fitzgen@gmail.com>"
+criteria = "safe-to-deploy"
+version = "3.9.1"
+notes = "I am the author of this crate."
+
 [[audits.cc]]
 who = "Alex Crichton <alex@alexcrichton.com>"
 criteria = "safe-to-deploy"