Also fix GetPropertyDescriptorWithInterceptor so that it only calls the
interceptor once.

R=ahaas@chromium.org, franzih@chromium.org

Bug: node:17480, node:17481
Change-Id: I2c3813f80df2962ec909bae7267884ce0b8ccbef
Reviewed-on: https://chromium-review.googlesource.com/816515
Commit-Queue: Franziska Hinkelmann <franzih@chromium.org>
Reviewed-by: Franziska Hinkelmann <franzih@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50260}