Add more OWNERS and set noparent for some sub-directories.

R=danno@chromium.org

Review URL: https://codereview.chromium.org/1285543002

Cr-Commit-Position: refs/heads/master@{#30128}

src/compiler/OWNERS

+set noparent
+
+bmeurer@chromium.org
+jarin@chromium.org
+mstarzinger@chromium.org
 titzer@chromium.org

src/debug/OWNERS

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

src/full-codegen/OWNERS

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

src/heap/OWNERS

+set noparent
+
 hpayer@chromium.org
+mlippautz@chromium.org
+ulan@chromium.org

src/ic/OWNERS

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

src/snapshot/OWNERS

+set noparent
+
 verwaest@chromium.org
+vogelheim@chromium.org
 yangguo@chromium.org