fixed handling of data URI schemes in Intent.toUri

Data URIs in intents can use schemes with digits and some special
characters (see RFC 2396 and 3986). This patch fixes how these
data URIs are handled by Intent.toUri to support these schemes.

Bug: 63930680
Test: run cts android.content.cts.IntentTest#testUris
Change-Id: I0dbb72325f59f372abba83be9e14c59d5665a053
Signed-off-by: Christopher Schuster <levjj@google.com>