Move public StreamReader/Writer to CoreLib (#15884)

Author: jkotas

src/mscorlib/Resources/Strings.resx

@@ -3145,6 +3145,9 @@
   <data name="ObjectDisposed_ObjectName_Name" xml:space="preserve">
     <value>Object name: '{0}'.</value>
   </data>
+  <data name="ObjectDisposed_WriterClosed" xml:space="preserve">
+    <value>Cannot write to a closed TextWriter.</value>
+  </data>
   <data name="ObjectDisposed_ReaderClosed" xml:space="preserve">
     <value>Cannot read from a closed TextReader.</value>
   </data>
@@ -3697,4 +3700,7 @@
   <data name="Arg_TypeNotSupported" xml:space="preserve">
     <value>Specified type is not supported</value>
   </data>
+  <data name="IO_InvalidReadLength" xml:space="preserve">
+    <value>The read operation returned an invalid length.</value>
+  </data>
 </root>

src/mscorlib/System.Private.CoreLib.csproj

@@ -583,8 +583,6 @@
     <Compile Include="$(BclSourcesRoot)\System\Globalization\EncodingDataItem.Unix.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Globalization\GlobalizationMode.Unix.cs" />
     <Compile Include="$(BclSourcesRoot)\System\IO\FileSystemEnumerable.cs" />
-    <Compile Include="$(BclSourcesRoot)\System\IO\TextReader.cs" />
-    <Compile Include="$(BclSourcesRoot)\System\IO\StreamReader.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Runtime\Versioning\CompatibilitySwitch.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Threading\ClrThreadPoolBoundHandle.Unix.cs" />
     <Compile Include="$(BclSourcesRoot)\System\TimeZoneInfo.Unix.cs" />

src/mscorlib/shared/System.Private.CoreLib.Shared.projitems

@@ -216,6 +216,10 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\IO\PinnedBufferMemoryStream.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\IO\SeekOrigin.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\IO\StreamHelpers.CopyValidation.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\IO\StreamReader.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\IO\StreamWriter.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\IO\TextReader.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\IO\TextWriter.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\IO\UnmanagedMemoryAccessor.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\IO\UnmanagedMemoryStream.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\IO\UnmanagedMemoryStreamWrapper.cs" />