Fix update-dependencies.ps1 and build scripts to no longer use restore --infer-runtimes.

Also, update-dependencies.ps1 doesn't use $PSScriptRoot everywhere.  Instead use $RepoRoot.

build_projects/dotnet-cli-build/build.ps1

@@ -68,7 +68,7 @@ $env:PATH = "$env:DOTNET_INSTALL_DIR;$env:PATH"
 # Restore the build scripts
 Write-Host "Restoring Build Script projects..."
 pushd "$PSScriptRoot\.."
-dotnet restore --infer-runtimes
+dotnet restore
 if($LASTEXITCODE -ne 0) { throw "Failed to restore" }
 popd
 

build_projects/dotnet-cli-build/build.sh

@@ -102,7 +102,7 @@ fi
 echo "Restoring Build Script projects..."
 (
     cd "$DIR/.."
-    dotnet restore --infer-runtimes
+    dotnet restore
 )
 
 # Build the builder