Remove 'read_only': 1 from most .isolate files.

These were mostly due to blind copy-paste. read_only:1 is the default so there's
no point in specifying it.

As per crbug.com/342913, only unit_tests has issue with running from read only
files.

R=jam@chromium.org
BUG=116251

Review URL: https://codereview.chromium.org/1240303002

Cr-Commit-Position: refs/heads/master@{#339490}
10 files changed