Make ObjectLiteral::is_simple() false for literals containing computed
property names, which causes IsCompileTimeValue() to return false and
thus force code to be generated for setting up such properties. This
mirrors the handling of '__proto__' in literals.

BUG=v8:4387
LOG=y

Review URL: https://codereview.chromium.org/1307943007

Cr-Commit-Position: refs/heads/master@{#30362}