feat: include if synchronous load in ModuleLoader

[dsherret]

Part of the fix for denoland/deno#26136 -- this will allow us to tell we're doing a sync import and then to use a different executor for deno_graph that doesn't spawn the future in the tokio runtime.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 92.04545% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.70%. Comparing base (0c7f83e) to head (4cb60d0).
⚠️ Report is 357 commits behind head on main.

Files with missing lines	Patch %	Lines
core/modules/loaders.rs	68.75%	5 Missing ⚠️
core/modules/tests.rs	66.66%	1 Missing ⚠️
core/source_map.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1219      +/-   ##
==========================================
- Coverage   81.43%   79.70%   -1.74%     
==========================================
  Files          97      100       +3     
  Lines       23877    26048    +2171     
==========================================
+ Hits        19445    20761    +1316     
- Misses       4432     5287     +855     

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[bartlomieju]

Good idea with the option bag