Miscellaneous inlining improvements

Add `#[inline]` to a few trivial non-generic methods from a perf report
that otherwise wouldn't be candidates for inlining.

compiler/rustc_query_system/src/dep_graph/graph.rs

@@ -59,6 +59,7 @@ pub enum DepNodeColor {
 }
 
 impl DepNodeColor {
+    #[inline]
     pub fn is_green(self) -> bool {
         match self {
             DepNodeColor::Red => false,