Expose SerializationInfo.UpdateValue for corefx
ObjectManager in corefx needs to access to SerializationInfo.UpdateValue, which is currently internal. We don't need to expose UpdateValue in a public contract (which would necessitate adding it to desktop), but by making it public we can give corefx the functionality it needs without needing to move a whole bunch more down from corefx into the runtime.
Commit migrated from https://github.com/dotnet/coreclr/commit/
1db5d5a1d9ed28b088f1e808096ca9b330bb2bac