Add source-build patch to address arcade bootstrap issue

src/SourceBuild/tarball/patches/arcade/0001-Resolve-NU1603-issue-w-System.Reflection.Metadata-du.patch

@@ -0,0 +1,28 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: MichaelSimons <msimons@microsoft.com>
+Date: Fri, 18 Feb 2022 15:11:39 +0000
+Subject: [PATCH] Resolve NU1603 issue w/System.Reflection.Metadata during
+ bootstrapping
+
+---
+ .../Microsoft.DotNet.PackageTesting.csproj                 | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git a/src/Microsoft.DotNet.PackageTesting/Microsoft.DotNet.PackageTesting.csproj b/src/Microsoft.DotNet.PackageTesting/Microsoft.DotNet.PackageTesting.csproj
+index 824dc8b..07697f8 100644
+--- a/src/Microsoft.DotNet.PackageTesting/Microsoft.DotNet.PackageTesting.csproj
++++ b/src/Microsoft.DotNet.PackageTesting/Microsoft.DotNet.PackageTesting.csproj
+@@ -8,6 +8,13 @@
+     <IsPackable>true</IsPackable>
+   </PropertyGroup>
+ 
++  <!-- During bootstrapped source-builds, the following situation can occur:
++  Microsoft.CodeAnalysis.Common z.b.c depends on System.Reflection.Metadata (>= x.y.z) but System.Reflection.Metadata x.y.z was not found.
++  An approximate best match of System.Reflection.Metadata x.y.(z+1) was resolved. -->
++  <PropertyGroup Condition="'$(DotNetBuildFromSource)' == 'true'">
++    <NoWarn>$(NoWarn);NU1603</NoWarn>
++  </PropertyGroup>
++
+   <ItemGroup>
+     <PackageReference Include="Microsoft.Build" Version="$(MicrosoftBuildVersion)" Publish="false" />
+     <PackageReference Include="Microsoft.Build.Tasks.Core" Version="$(MicrosoftBuildTasksCoreVersion)" Publish="false" />