Dumb typo introduced in refs/heads/master@{#29306}. I thought I was turning on
report_exceptions in Shell::ExecuteString, but instead I turned on print_result
(which assumes an interactive debugger and a HandleScope for the
utility_context_).

BUG=chromium:504727,chromium:504728
R=mstarzinger@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/1219563002

Cr-Commit-Position: refs/heads/master@{#29350}