Upgrade to regalloc2 0.3.1. (#4483)

This includes some changes from @bnjbvr to the trace-logging/annotation
to reduce overhead when logging is enabled but only non-RA2 subsystems
are at `Trace` level.

Cargo.lock

@@ -2363,9 +2363,9 @@ dependencies = [
 
 [[package]]
 name = "regalloc2"
-version = "0.3.0"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd4159f16b35683a517cc0318997f8fbe89523ed03526c90e267bed6d66ced36"
+checksum = "76ff2e57a7d050308b3fde0f707aa240b491b190e3855f212860f11bb3af4205"
 dependencies = [
  "fxhash",
  "log",

cranelift/codegen/Cargo.toml

@@ -23,7 +23,7 @@ serde = { version = "1.0.94", features = ["derive"], optional = true }
 bincode = { version = "1.2.1", optional = true }
 gimli = { version = "0.26.0", default-features = false, features = ["write"], optional = true }
 smallvec = { version = "1.6.1" }
-regalloc2 = { version = "0.3.0", features = ["checker"] }
+regalloc2 = { version = "0.3.1", features = ["checker"] }
 souper-ir = { version = "2.1.0", optional = true }
 # It is a goal of the cranelift-codegen crate to have minimal external dependencies.
 # Please don't add any unless they are essential to the task of creating binary