Consolidate the "unparsed" option value tracking.

In preparation for linking the parsed and unparsed values of options, consolidate and standardize our representation of the flag values as we received them (what is meant by "unparsed" values in this case). This was being done separately in ParseOptionResult, which, with extra context added, is being folded into UnparsedOptionValueDescription. We now track how an option was provided and where it came from for all option parsing.

RELNOTES: None.
PiperOrigin-RevId: 168682082
GitOrigin-RevId: 5fe8e6629e09ce44c6835d1b8f3a36bc3d69f131
Change-Id: I3964b563289ee39ab3a9a7ac496ed033459546c0
7 files changed
tree: 6429c1afdee36fefbde5e35fa7b3c6547ff7a2f9
  1. java/
  2. test/