Revert EncodingForwarder (#10805)

* Revert "Remove TODO on throwing exception"

This reverts commit 467f06d.

* Revert "Move the SecuritySafeCritical attributes to EncodingForwarder"

This reverts commit a64020c.

* Revert "Add note on UTF8Encoding.GetByteCount to EncodingForwarder"

This reverts commit a4192dc.

* Revert "Fix CoreFX test failures"

This reverts commit 4fd1bfe.

* Revert "[UTF8Encoding] Remove unncessary comments"

This reverts commit 1f9cd67.

* Revert "[UTF7Encoding] Remove unncessary comments"

This reverts commit e1818e6.

* Revert "[UTF32Encoding] Remove unncessary comments"

This reverts commit ad1ad35.

* Revert "[UnicodeEncoding] Remove unncessary comments"

This reverts commit f09b521.

* Revert "[EncodingNLS] Remove unncessary comments"

This reverts commit 95ff597.

* Revert "[ASCIIEncoding] Remove unncessary comments"

This reverts commit 77fa0fb.

* Revert "Use EncodingForwarder for GetString(byte[], int, int)"

This reverts commit 372fcd3.

* Revert "Use EncodingForwarder for GetChars(byte*, int, char*, int)"

This reverts commit ab47c22.

* Revert "Use EncodingForwarder for GetChars(byte[], int, int, char[], int)"

This reverts commit 860434d.

* Revert "Use EncodingForwarder for GetCharCount(byte*, int)"

This reverts commit f83ecbe.

* Revert "Use EncodingForwarder for GetCharCount(byte[], int, int)"

This reverts commit 6de8ede.

* Revert "Use EncodingForwarder for GetBytes(char*, int, byte*, int)"

This reverts commit 7c771b8.

* Revert "Use EncodingForwarder for GetBytes(char[], int, int, byte[], int)"

This reverts commit 0889431.

* Revert "Use EncodingForwarder for GetBytes(string, int, int, byte[], int)"

This reverts commit fa55fd7.

* Revert "Use EncodingForwarder for GetByteCount(char*, int)"

This reverts commit 56c687e.

* Revert "Rename the chars parameter in a comment"

This reverts commit 9668b5f.

* Revert "Use EncodingForwarder for GetByteCount(string)"

This reverts commit e614790.

* Revert "Use EncodingForwarder for GetByteCount(char[], int, int)"

This reverts commit ebfc3ce.

src/mscorlib/mscorlib.shared.sources.props

@@ -991,7 +991,6 @@
     <TextSources Include="$(BclSourcesRoot)\System\Text\EncoderFallback.cs" />
     <TextSources Include="$(BclSourcesRoot)\System\Text\EncoderReplacementFallback.cs" />
     <TextSources Include="$(BclSourcesRoot)\System\Text\Encoding.cs" />
-    <TextSources Include="$(BclSourcesRoot)\System\Text\EncodingForwarder.cs" />
     <TextSources Include="$(BclSourcesRoot)\System\Text\EncodingInfo.cs" />
     <TextSources Include="$(BclSourcesRoot)\System\Text\EncodingNLS.cs" />
     <TextSources Include="$(BclSourcesRoot)\System\Text\EncodingProvider.cs" />