Add more OWNERS for components.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/1293453002 .

Cr-Commit-Position: refs/heads/master@{#30147}

src/debug/OWNERS

 set noparent
 
+bmeurer@chromium.org
 mvstanton@chromium.org
 ulan@chromium.org
 verwaest@chromium.org

src/full-codegen/OWNERS

 set noparent
 
 bmeurer@chromium.org
+jarin@chromium.org
 jkummerow@chromium.org
 mstarzinger@chromium.org
 verwaest@chromium.org

src/heap/OWNERS

@@ -2,4 +2,5 @@ set noparent
 
 hpayer@chromium.org
 mlippautz@chromium.org
+mstarzinger@chromium.org
 ulan@chromium.org

src/ic/OWNERS

 set noparent
 
+bmeurer@chromium.org
+ishell@chromium.org
 jkummerow@chromium.org
 mvstanton@chromium.org
 verwaest@chromium.org