test_sources_list() relied on <https://servo.org/js/load-table.js> to
test scripts loaded from multiple origins, but that file was deleted a
couple of weeks ago. this patch adds a second internal web server, then
replaces that load with scripts loaded from two distinct origins:
<http://127.0.0.1:10000> and <http://127.0.0.1:10001>.

fixing that test revealed an impl bug where inline module scripts
containing `import` statements may never get their source contents
populated. this is because the logic for populating source contents for
inline scripts only applied to source actors created *before* we
finished parsing the page. we assumed that inline scripts always block
the parser, but this is not the case. this patch ensures that inline
source contents can be populated for source actors created after parse.

Testing: adds a new test,
test_source_content_with_inline_module_import_external()
Fixes: part of servo#36325

Signed-off-by: Delan Azabani <dazabani@igalia.com>
Co-authored-by: atbrakhi <atbrakhi@igalia.com>

Co-authored-by: atbrakhi <atbrakhi@igalia.com>
Signed-off-by: Delan Azabani <dazabani@igalia.com>

Co-authored-by: atbrakhi <atbrakhi@igalia.com>
Signed-off-by: Delan Azabani <dazabani@igalia.com>

Co-authored-by: atbrakhi <atbrakhi@igalia.com>
Signed-off-by: Delan Azabani <dazabani@igalia.com>

in #38359, we intended to land some fixes to the devtools tests, but we
failed to actually include those fixes in the patch. this patch adds a
second internal web server, then reworks test_sources_list() to load
scripts from the two distinct origins of our internal web servers:
<http://127.0.0.1:10000> and <http://127.0.0.1:10001>.

Testing: covered by existing devtools tests, which now actually pass
Fixes: part of #36325

---------

Signed-off-by: Delan Azabani <dazabani@igalia.com>
Co-authored-by: atbrakhi <atbrakhi@igalia.com>

…38516) (wd)

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