Parse relative URLs inside parentheses without function names

Some frameworks/libraries override Error#stack to print location strings
enclosed in parentheses even when there is no preceding function name
(e.g. "at (foo.js:10:5)"). Standard V8 only emits "at functionName
(foo.js:10:5)" (with function name and parens) or "at foo.js:10:5" (no
function name, no parens).

This change updates DetailedErrorStackParser to explicitly handle stack
frames where the location string is entirely enclosed in parentheses. By
adding a check for content that starts and ends with parentheses when no
function name is detected, the parser can now correctly strip them and
extract the location. This prevents parsing failures on overridden error
stacks.

Bug: 485142682
Change-Id: I0f176ae16afee8bb32d79c76ed7299a979803deb
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/7924667
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Eric Leese <leese@chromium.org>