Add CA2024: Do not use 'StreamReader.EndOfStream' in async methods

[mpidash]

Fixes dotnet/runtime#98834.

Rule ID	CA2024
Title	Do not use 'StreamReader.EndOfStream' in async methods
Message	Do not use '{0}' in an async method
Description	The property 'StreamReader.EndOfStream' can cause unintended synchronous blocking when no data is buffered. Instead, use 'StreamReader.ReadLineAsync' directly, which returns 'null' when reaching the end of the stream.
Category	Reliability
Severity	Warning

This analyzer detects when StreamReader.EndOfStream is used in an async method, which can prevent I/O from being done asynchronously.

---

I've tested against dotnet/runtime, dotnet/roslyn and dotnet/aspnetcore and found no violations.

I've also added a reference to EndOfStream in an async method in runtime for testing, which leads to the following message: warning CA2024: Do not use 'sr.EndOfStream' in an async method.

[codecov]

Codecov Report

Attention: Patch coverage is 98.34906% with 7 lines in your changes missing coverage. Please review.

Project coverage is 96.50%. Comparing base (d6e7d82) to head (e59b83a).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #7390    +/-   ##
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  Coverage   96.50%   96.50%            
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  Files        1448     1450     +2     
  Lines      346895   347319   +424     
  Branches    11404    11409     +5     
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+ Hits       334755   335186   +431     
+ Misses       9250     9242     -8     
- Partials     2890     2891     +1     

[stephentoub]

Other than some changes for the tests, this LGTM. Thanks for working on this.

[mpidash]

I've addressed your feedback, thanks for the review!

[stephentoub]

thanks!