[CodeView] Add support for dumping binary annotations

Binary annotations are encoded along the lines of UTF-8 and ECI but with
a few minor differences.

The algorithm specified in "ECMA-335 CLI Section II.3.2 - Blobs and
Signatures" is used to compress binary annotations.  Signed binary
annotations are encoded like unsigned annotations except the sign bit is
rotated left to reduce the number of bits needed to be encoded.

llvm-svn: 257742