Fix Windows CI by scoping IntermediateOutputPath per framework

[thejambi]

Directory.Build.props sets AppendTargetFrameworkToOutputPath=false so that OutputPath can place output under artifacts/$(Configuration)/$(TargetFramework) itself. That flag also strips $(TargetFramework) from IntermediateOutputPath, so all three target frameworks of a multi-targeted project shared a single obj folder - including the reference assembly under obj/ref. Whichever framework built last owned it.

ProjectReference resolution reads that reference assembly, so the netstandard2.0 compile of SIL.LCModel could be handed the net8.0 build of SIL.LCModel.Core:

CSC : error CS1705: Assembly 'SIL.LCModel.Core' ... uses
'System.Drawing.Primitives, Version=8.0.0.0' which has a higher version than
referenced assembly 'System.Drawing.Primitives, Version=4.0.2.0'
[SIL.LCModel.csproj::TargetFramework=netstandard2.0]

Build ordering decided whether this hit, which is why Windows failed while Linux stayed green. #394 removed the OutDir override in SIL.LCModel and fixed the bin side of the same problem; the intermediate side kept sharing one path.

Set IntermediateOutputPath to obj/$(Configuration)/$(TargetFramework)/ in Directory.Build.props, and drop the obj/x86/$(Configuration)/ override in SIL.LCModel.Core.csproj that predates multi-targeting and now conflicts with it - Platform is Any CPU repo-wide, so the x86 segment bought nothing. OutputPath and the artifacts layout are unchanged.

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This change is 

[github-actions]

LCM Tests

    16 files  +    8      16 suites  +8   2m 9s ⏱️ + 1m 6s
 2 875 tests ±    0   2 855 ✅ +   14   20 💤  - 14  0 ❌ ±0 
11 448 runs  +5 724  11 280 ✅ +5 638  168 💤 +86  0 ❌ ±0 

Results for commit a8af51e. ± Comparison against base commit 6e97da6.

♻️ This comment has been updated with latest results.

[jasonleenaylor]

src/SIL.LCModel.Core/SIL.LCModel.Core.csproj line 89 at r1 (raw file):

  <PropertyGroup>
    <!-- IntermediateOutputPath comes from Directory.Build.props, which scopes it per target

This comment is unnecessary, no one will come to this file and go 'huh, why is this property that I don't know about mssing?'

[thejambi]

src/SIL.LCModel.Core/SIL.LCModel.Core.csproj line 89 at r1 (raw file):

Previously, jasonleenaylor (Jason Naylor) wrote…

This comment is unnecessary, no one will come to this file and go 'huh, why is this property that I don't know about mssing?'

Comments have been removed.

[jasonleenaylor]

@jasonleenaylor reviewed 2 files and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on thejambi).