`parseUrl` from `sdk-trace-web` does not support relative paths anymore

[pichlermarc]

The changes from #2689 might have introduced a breaking change to 1.1.0 that causes relative paths to not be parsed anymore.

The current implementation of parseUrl now throws when providing relative paths as parameter as it calls the URL constructor with it. It previously tolerated relative paths. This caused tests for instrumentation-fetch and instrumentation-xml-http-request in #2871 to fail when updating the dependency to sdk-trace-web from 1.0.1 to 1.1.1.

This might also affect others that are upgrading from 1.0.x to 1.1.0/1.1.1

[legendecas]

I would like this to wait for #2892 so that we can properly test it with instrumentation-fetch or instrumentation-xhr. parseUrl is not used anywhere in sdk-trace-web so it is not so easy to test it well.