[compiler] Make jkummerow an owner of wasm-compiler.*

jkummerow made many changes to wasm-compiler.cc and co, and is
more than qualified to be an owner.

R=clemensb@chromium.org

Change-Id: I05cb1b7c73627d4c3fe59f154c1267c7cd44a2d8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2307314Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68946}

src/compiler/OWNERS

@@ -13,6 +13,7 @@ per-file wasm-*=bbudge@chromium.org
 per-file wasm-*=binji@chromium.org
 per-file wasm-*=clemensb@chromium.org
 per-file wasm-*=gdeepti@chromium.org
+per-file wasm-*=jkummerow@chromium.org
 
 per-file int64-lowering.*=ahaas@chromium.org