Fix a bunch of Charset tests.

The isRegistered test is still failing. The problem is that icu4c's
convrtrs.txt has names like "windows-1252" that are both the canonical
name for one charset and an alias for another legacy charset. I need
to work out how to resolve that.

Bug: 10210999

(cherry picked from commit ea1caf4ccc5c2255f384c0774aa9e055763a6a41)

Change-Id: I83cf1b9ae1d29f9956f443ef914a3e473e0f4692
17 files changed