Fix the build to work well under OSS conditions.

Mainly:
1.   disables some tests that fail in the OSS branch.
2.   Fakesigns the diagnostics implementation assemblies
3.   Fakesign the TestResourcesProprietary dll, which is deployed via nuget. (changeset 1386520)

Src/Compilers/CSharp/Test/Semantic/Semantics/NameCollisionTests.cs

@@ -1867,7 +1867,7 @@ static void Main()
                 );
         }
 
-        [Fact]
+        [Fact(Skip = "https://roslyn.codeplex.com/workitem/450")]
         [WorkItem(879811, "DevDiv")]
         public void Bug879811_1()
         {

Src/Diagnostics/Roslyn/CSharp/CSharpRoslynDiagnosticAnalyzers.csproj

@@ -16,6 +16,7 @@
     <RootNamespace>Roslyn.Diagnostics.Analyzers.CSharp</RootNamespace>
     <AssemblyName>Roslyn.Diagnostics.Analyzers.CSharp</AssemblyName>
     <SolutionDir Condition="'$(SolutionDir)' == '' OR '$(SolutionDir)' == '*Undefined*'">..\..\..\..\</SolutionDir>
+    <NeedsFakeSign>true</NeedsFakeSign>
     <RestorePackages>true</RestorePackages>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' "></PropertyGroup>

Src/Diagnostics/Roslyn/Core/RoslynDiagnosticAnalyzers.csproj

@@ -15,6 +15,7 @@
     <RootNamespace>Roslyn.Diagnostics.Analyzers</RootNamespace>
     <AssemblyName>Roslyn.Diagnostics.Analyzers</AssemblyName>
     <SolutionDir Condition="'$(SolutionDir)' == '' OR '$(SolutionDir)' == '*Undefined*'">..\..\..\..\</SolutionDir>
+    <NeedsFakeSign>true</NeedsFakeSign>
     <RestorePackages>true</RestorePackages>
   </PropertyGroup>
   <ItemGroup Label="File References">

Src/Diagnostics/Roslyn/VisualBasic/BasicRoslynDiagnosticAnalyzers.vbproj

@@ -15,6 +15,7 @@
     <AssemblyName>Roslyn.Diagnostics.Analyzers.VisualBasic</AssemblyName>
     <DocumentationFile>Roslyn.Diagnostics.Analyzers.VisualBasic.xml</DocumentationFile>
     <SolutionDir Condition="'$(SolutionDir)' == '' OR '$(SolutionDir)' == '*Undefined*'">..\..\..\..\</SolutionDir>
+    <NeedsFakeSign>true</NeedsFakeSign>
     <RestorePackages>true</RestorePackages>
   </PropertyGroup>
   <ItemGroup Label="File References">

Src/Workspaces/CoreTest/WorkspaceTests/MSBuildWorkspaceTests.cs

@@ -440,7 +440,7 @@ public void TestMetadataReferenceHasBadHintPath()
             Assert.NotNull(csharpLib);
         }
 
-        [Fact, Trait(Traits.Feature, Traits.Features.Workspace)]
+        [Fact(Skip = "https://roslyn.codeplex.com/workitem/452"), Trait(Traits.Feature, Traits.Features.Workspace)]
         [WorkItem(531631, "DevDiv")]
         public void TestOpenProject_AssemblyNameIsPath()
         {
@@ -456,7 +456,7 @@ public void TestOpenProject_AssemblyNameIsPath()
             Assert.Equal(expectedOutputPath, Path.GetDirectoryName(project.OutputFilePath));
         }
 
-        [Fact, Trait(Traits.Feature, Traits.Features.Workspace)]
+        [Fact(Skip = "https://roslyn.codeplex.com/workitem/453"), Trait(Traits.Feature, Traits.Features.Workspace)]
         [WorkItem(531631, "DevDiv")]
         public void TestOpenProject_AssemblyNameIsPath2()
         {
@@ -875,7 +875,7 @@ public void TestOpenProject_WithUnrecognizedProjectReferenceFileExtension_SkipFa
             });
         }
 
-        [Fact, Trait(Traits.Feature, Traits.Features.Workspace)]
+        [Fact(Skip = "https://roslyn.codeplex.com/workitem/457"), Trait(Traits.Feature, Traits.Features.Workspace)]
         public void TestOpenProject_WithUnrecognizedProjectReferenceFileExtension_WithMetadata_SkipTrue_SucceedsByLoadingMetadata()
         {
             CreateFiles(GetMultiProjectSolutionFiles()
@@ -896,7 +896,7 @@ public void TestOpenProject_WithUnrecognizedProjectReferenceFileExtension_WithMe
             Assert.Equal(true, metaRefs.Any(r => r is PortableExecutableReference && ((PortableExecutableReference)r).Display.Contains("CSharpProject.dll")));
         }
 
-        [Fact, Trait(Traits.Feature, Traits.Features.Workspace)]
+        [Fact(Skip = "https://roslyn.codeplex.com/workitem/455"), Trait(Traits.Feature, Traits.Features.Workspace)]
         public void TestOpenProject_WithUnrecognizedProjectReferenceFileExtension_WithMetadata_SkipFalse_SucceedsByLoadingMetadata()
         {
             CreateFiles(GetMultiProjectSolutionFiles()
@@ -919,7 +919,7 @@ public void TestOpenProject_WithUnrecognizedProjectReferenceFileExtension_WithMe
             Assert.Equal(true, metaRefs.Any(r => r is PortableExecutableReference && ((PortableExecutableReference)r).Display.Contains("CSharpProject.dll")));
         }
 
-        [Fact, Trait(Traits.Feature, Traits.Features.Workspace)]
+        [Fact(Skip = "https://roslyn.codeplex.com/workitem/451"), Trait(Traits.Feature, Traits.Features.Workspace)]
         public void TestOpenProject_WithReferencedProject_LoadMetadata_ExistingMetadata_Succeeds()
         {
             CreateFiles(GetMultiProjectSolutionFiles()
@@ -958,7 +958,7 @@ public void TestOpenProject_WithReferencedProject_LoadMetadata_NonExistentMetada
             Assert.False(metaRefs.Any(r => !r.Properties.Aliases.IsDefault && r.Properties.Aliases.Contains("CSharpProject")));
         }
 
-        [Fact, Trait(Traits.Feature, Traits.Features.Workspace)]
+        [Fact(Skip = "https://roslyn.codeplex.com/workitem/454"), Trait(Traits.Feature, Traits.Features.Workspace)]
         public void TestOpenProject_UpdateExistingReferences()
         {
             CreateFiles(GetMultiProjectSolutionFiles()