Fixup destkop tests

src/Compilers/CSharp/Test/Emit/Emit/CompilationEmitTests.cs

@@ -3730,7 +3730,7 @@ public void IllegalNameOverride()
         }
 
         // Verify via MetadataReader - comp option
-        [Fact]
+        [ConditionalFact(typeof(WindowsDesktopOnly), Reason = ConditionalSkipReason.TestExecutionNeedsDesktopTypes)]
         public void CheckUnsafeAttributes3()
         {
             string source = @"
@@ -3765,7 +3765,7 @@ public static void Main()
         }
 
         // Verify via MetadataReader - comp option, module case
-        [Fact]
+        [ConditionalFact(typeof(WindowsDesktopOnly), Reason = ConditionalSkipReason.TestExecutionNeedsDesktopTypes)]
         public void CheckUnsafeAttributes4()
         {
             string source = @"
@@ -3787,7 +3787,7 @@ public static void Main()
         }
 
         // Verify via MetadataReader - attr in source
-        [Fact]
+        [ConditionalFact(typeof(WindowsDesktopOnly), Reason = ConditionalSkipReason.TestExecutionNeedsDesktopTypes)]
         public void CheckUnsafeAttributes5()
         {
             // Writing the attributes in the source should have the same effect as the compilation option.
@@ -3834,7 +3834,7 @@ public static void Main()
         }
 
         // Verify via MetadataReader - two attrs in source, same action
-        [Fact]
+        [ConditionalFact(typeof(WindowsDesktopOnly), Reason = ConditionalSkipReason.TestExecutionNeedsDesktopTypes)]
         public void CheckUnsafeAttributes6()
         {
             string source = @"
@@ -3895,7 +3895,7 @@ public static void Main()
         }
 
         // Verify via MetadataReader - two attrs in source, different actions
-        [Fact]
+        [ConditionalFact(typeof(WindowsDesktopOnly), Reason = ConditionalSkipReason.TestExecutionNeedsDesktopTypes)]
         public void CheckUnsafeAttributes7()
         {
             string source = @"
@@ -3962,7 +3962,7 @@ public static void Main()
         }
 
         // Verify via MetadataReader - one attr in source, one synthesized, same action
-        [Fact]
+        [ConditionalFact(typeof(WindowsDesktopOnly), Reason = ConditionalSkipReason.TestExecutionNeedsDesktopTypes)]
         public void CheckUnsafeAttributes8()
         {
             string source = @"
@@ -4019,7 +4019,7 @@ public static void Main()
         }
 
         // Verify via MetadataReader - one attr in source, one synthesized, different actions
-        [Fact]
+        [ConditionalFact(typeof(WindowsDesktopOnly), Reason = ConditionalSkipReason.TestExecutionNeedsDesktopTypes)]
         public void CheckUnsafeAttributes9()
         {
             string source = @"

src/Test/Utilities/Portable/Assert/ConditionalFactAttribute.cs

@@ -37,6 +37,11 @@ public static class ConditionalSkipReason
 
         public const string TestExecutionHasCOMInterop = "Test execution depends on COM Interop";
         public const string TestHasWindowsPaths = "Test depends on Windows style paths";
+
+        /// <summary>
+        /// Edit and continue is only supported on desktop at the moment.
+        /// </summary>
+        public const string EditAndContinueRequiresDesktop = "Edit and continue is only supported on desktop";
     }
 
     public class ConditionalFactAttribute : FactAttribute