This concerns formatting of calls to, e.g., Math.acos in stack traces,
in which the receiver is an object with an attached toString tag. If
such a tag exists, use it to format the receiver typename to ensure that
the stack trace includes 'Math.acos' instead of 'Object.acos'.

R=yangguo@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2110683007
Cr-Commit-Position: refs/heads/master@{#37513}