Rollup merge of rust-lang#55857 - andjo403:rmdep, r=Mark-Simulacrum

remove unused dependency

Author: kennytm

src/Cargo.lock

@@ -2170,7 +2170,6 @@ dependencies = [
  "graphviz 0.0.0",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "parking_lot_core 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-rayon 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-rayon-core 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",

src/librustc_data_structures/Cargo.toml

@@ -16,7 +16,6 @@ serialize = { path = "../libserialize" }
 graphviz = { path = "../libgraphviz" }
 cfg-if = "0.1.2"
 stable_deref_trait = "1.0.0"
-parking_lot_core = "0.2.8"
 rustc-rayon = "0.1.1"
 rustc-rayon-core = "0.1.1"
 rustc-hash = "1.0.1"