Try to fix a perf regression by updating log

Upgrade `log` to `0.4` in multiple crates.

src/librustc_data_structures/Cargo.toml

@@ -9,7 +9,7 @@ path = "lib.rs"
 crate-type = ["dylib"]
 
 [dependencies]
-log = "0.3"
+log = "0.4"
 serialize = { path = "../libserialize" }
 cfg-if = "0.1.2"
 stable_deref_trait = "1.0.0"
@@ -17,4 +17,4 @@ parking_lot_core = "0.2.8"
 
 [dependencies.parking_lot]
 version = "0.5"
-features = ["nightly"]
+features = ["nightly"]