Revert "Add toStringTag value on JSG resource types"

[mikea]

Reverts #1607

Breaks downstream trace test

[jasnell]

@mikea ... how was the internal repo test broken? Does the test assume a particular output when an object to stringified? e.g. [object Object] vs. [object Foo]? Depending on exactly how that test was broken this change might end up having to go behind a compat flag.

[mikea]

@mikea ... how was the internal repo test broken? Does the test assume a particular output when an object to stringified? e.g. [object Object] vs. [object Foo]? Depending on exactly how that test was broken this change might end up having to go behind a compat flag.

hard for me to say what's wrong: there's so much output in the test. All I know is that Can log JSON edge cases subtest fails with this commit and passes without. @garrettgu10 has the build link (PR 7264)

[garrettgu10]

@jasnell It looks like the test does assume a particular output when an object is stringified:

Expected: ["[object Object]"], actual: ["[object Headers]"]

[kentonv]

It sounds like the test just needs to be updated, but it's important to merge those downstream updates at the same time as the workerd changes.