Use a custom build of V8 with leaptiering off (#37494)

Work around https://issues.chromium.org/issues/419147069.
I built V8 with `GN_ARGS=v8_enable_leaptiering=false` and uploaded the binaries to our fork of rusty_v8.

GitOrigin-RevId: bafdbaf7bc847a3891be14e81aabd44352a4f306

Author: goffrie

.cargo/config.toml

@@ -1,6 +1,10 @@
 [env]
 CARGO_WORKSPACE_ROOT = { value = "", relative = true }
 CHRONO_TZ_TIMEZONE_FILTER = "US/Pacific"
+# HACK: use custom build with leaptiering off,
+# until either https://issues.chromium.org/issues/419147069 is fixed or we can
+# turn on pointer compression
+RUSTY_V8_MIRROR = "https://github.com/get-convex/rusty_v8/releases/download"
 
 [target.aarch64-unknown-linux-gnu]
 rustflags = ["-Ctarget-cpu=neoverse-n1", "-Cforce-frame-pointers=yes"]