[AOT] suppress IL2026

[Yun-Ting]

Towards #3429
Related to: dotnet/runtime#85274

Changes

Suppress non-real issues (https://learn.microsoft.com/en-us/dotnet/core/deploying/trimming/trim-warnings/il2026) with the approach from this doc:
https://learn.microsoft.com/en-us/dotnet/core/deploying/trimming/prepare-libraries-for-trimming#unconditionalsuppressmessage

list of warnings with this code change:
testlog_2.txt

Merge requirement checklist

• CONTRIBUTING guidelines followed (nullable enabled, static analysis, etc.)
• Unit tests added/updated
• Appropriate CHANGELOG.md files updated for non-trivial changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

Merging #4428 (74e0063) into main (c73a70d) will increase coverage by 0.69%.
The diff coverage is 0.00%.

❗ Current head 74e0063 differs from pull request most recent head 3729720. Consider uploading reports for the commit 3729720 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4428      +/-   ##
==========================================
+ Coverage   83.35%   84.05%   +0.69%     
==========================================
  Files         313      312       -1     
  Lines       12513    12339     -174     
==========================================
- Hits        10430    10371      -59     
+ Misses       2083     1968     -115     

Impacted Files	Coverage Δ
...nTelemetry/Internal/OpenTelemetrySdkEventSource.cs	82.02% <ø> (+1.81%)	⬆️
...nal/Shims/UnconditionalSuppressMessageAttribute.cs	0.00% <0.00%> (ø)

... and 12 files with indirect coverage changes

[eerhardt]

Looks good to me. Thanks for all the work here.