[Backport 8.0] [IIS] Manually parse exe bitness (#61894)

[BrennanConroy]

Backport of #61894

[IIS] Manually parse exe bitness

Description

In the AspNetCoreModule for IIS we have a check that dotnet.exe is the same architecture as the worker process (w3wp.exe). We used the windows function GetBinaryTypeW to determine this information, which while correct has raised some concerns since it loads the exe into executable space.

This PR changes the code to manually parse the exe file headers which is a well known format and use that information for the bitness check. This avoids loading the exe in executable space and still lets us check that the bitness matches.

Customer Impact

We unnecessarily load the specified exe into executable space.

Regression?

• Yes
• No

Risk

• High
• Medium
• Low

Updating a non-critical check, so if it checks incorrectly it will only result in slightly worse program diagnosability on app run failure. Also did a bunch of testing on the code to make sure it shouldn't be possible to throw which would be problematic.

Verification

• Manual (required)
• Automated

Packaging changes reviewed?

• Yes
• No
• N/A

[dotnet-policy-service]

Hi @@BrennanConroy. This PR was just approved to be included in the upcoming servicing release. Somebody from the @dotnet/aspnet-build team will get it merged when the branches are open. Until then, please make sure all the CI checks pass and the PR is reviewed.