Fix 22730 - Promote imported files (-i) to root module before parsing the declarations.

[MoonlightSentinel]

#13224 changed the parser s.t. unittests from non-root modules are skipped, i.e. not even parsed. The new behaviour didn't work as expected when combined with -i because it promoted imported files to root modules after the parser processed the entire file.

The first commit splits the module parsing into dedicated methods for the module declaration and content. The second commit then moves the existing checks s.t. they are applied immediatly after the module declaration and before the first unittest.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	22730	regression	master: "dmd -i" doesn't include unit tests from imported modules

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "stable + dmd#13654"

[Geod24]

I'm not sure I follow the logic. Why is the static assert in lib.ignores.unittests not triggering ?

[MoonlightSentinel]

Why is the static assert in lib.ignores.unittests not triggering ?

imports.skipped_unittest_lib doesn't match any -i=<pattern> and hence remains a non-root module, causing the parser to skip any unittest found within the file.

[MoonlightSentinel]

I've changed the test to a compilable example s.t. errors won't be hidden if the order of semantic evaluation is changed. (i.e. the "good" static assert(false) in the root module triggers before that non-root one)