Test that network errors create resource timing entries

[noamr]

See behavior change/clarification in whatwg/fetch#1215

When a network error occurs during fetch, a resource timing entry should still be created, with only the start/end timing to avoid exposing potential cross-origin information.

There are many different scenarios for network errors, they should be sufficiently covered.

[noamr]

Tests for network errors for the fetch API:

• CORS failure
• CSP failure
• about:*
• blob:* non-GET or non-blob
• Aborted blob request
• Invalid data:* URL
• file: URLs
• unrecognized scheme
• No follow redirects
• Bad redirect location
• More than 20 redirects
• Redirect to non-HTTP
• inflight is larger than 64KB
• Aborted HTTP Request
• only-if-cached when not in cache
• Connection failure

Tests for network errors not applicable for the fetch API:

• nosniff (script only)
• wrong mime-type (script only)