Add feature removal based on XML substitutions (#1132)

* Add feature removal based on XML substitutions

* Don't use Dictionary.TryAdd on mono

* Add doc comments to the task

* Change feature argument and description

* Use High importance for invalid features

And for invalid feature settings

* Look for embedded ILLink.Substitutions.xml

* Undo indentation change

* Tweak description slighty

* Respond to feedback

- Don't check for multiple feature settings of same feature
- Put substitution step after BlacklistStep
- Require a location in ctors that take an XPathDocument

* Remove --exclude-feature from ILLink build

* Add steps in a consistent order

* Only allow passing boolean feature values

* Use new logging APIs

1 files changed, 3 insertions, 0 deletions

diff --git a/test/Mono.Linker.Tests.Cases/TestFramework/VerifyExpectModifiedAttributesWork.cs b/test/Mono.Linker.Tests.Cases/TestFramework/VerifyExpectModifiedAttributesWork.cs
index 3b3a7f015..787c5179e 100644
--- a/test/Mono.Linker.Tests.Cases/TestFramework/VerifyExpectModifiedAttributesWork.cs
+++ b/test/Mono.Linker.Tests.Cases/TestFramework/VerifyExpectModifiedAttributesWork.cs
@@ -8,6 +8,9 @@ namespace Mono.Linker.Tests.Cases.TestFramework {
 	/// This test is here to give some coverage to the attribute to ensure it doesn't break.  We need to leverage the ETW feature since it is the only
 	/// one that modifies bodies currently
 	/// </summary>
+#if NETCOREAPP
+	[IgnoreTestCase ("--exclude-feature is not supported on .NET Core")]
+#endif
 	[SetupLinkerArgument ("--exclude-feature", "etw")]
 	// Keep framework code that calls EventSource methods like OnEventCommand
 	[SetupLinkerCoreAction ("skip")]