devapp/owners: remove josharian from runtime

The runtime package contains multitudes.
I only care about a few of them.
The signal to noise ratio on changes is currently too low.

I hope that we will someday resume work on golang/go#11647,
and/or implement some devapp filters. (Keyword-based? File-based?)

Until then, I'm tapping out.

Change-Id: Ib3baabb44f3a9ee48d78dcb8234c3752e0e42278
Reviewed-on: https://go-review.googlesource.com/c/build/+/171702
Reviewed-by: Josh Bleecher Snyder <[email protected]>

devapp/owners/table.go

@@ -459,7 +459,7 @@ var entries = map[string]*Entry{
 	},
 	"go/src/runtime": {
 		Primary:   []Owner{austin, rsc, rlh, khr},
-		Secondary: []Owner{iant, dvyukov, josharian, martisch},
+		Secondary: []Owner{iant, dvyukov, martisch},
 	},
 	"go/src/runtime/cgo": {
 		Primary: []Owner{iant},