[build-presets] Build SourceKit-LSP in SwiftSyntaxCI tests

This would have caught rdar://101588779

Author: ahoppen

utils/build-presets.ini

@@ -1810,13 +1810,15 @@ swiftsyntax
 swiftsyntax-verify-generated-files
 skstresstester
 swiftevolve
+sourcekit-lsp
 skip-test-swift=false
 
 [preset: buildbot_swiftsyntax_linux]
 mixin-preset=mixin_swiftpm_package_linux_platform
 release
 assertions
 swiftsyntax
+sourcekit-lsp
 swiftsyntax-verify-generated-files
 
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