Accept IPvFuture syntax in Uri.

The RFC 3986 grammar for `[...]` addresses accepts
IPv6 addresses  and IPvFuture addresses, where the latter
have the form `'v' <hexDigit>+ '.' (<unreserved>|<sub-delim>|':')+`.

This allows the IPvFuture syntax, with no interpretation,
as the `host` of a `Uri`.

For now, the `Uri(host: ...)` constructor argument only allows
IPvFuture addresses that are already wrapped in `[...]` brackets,
and the `Uri.host` gette returns IPvFuture addresses including
brackets.
The `Uri(host:...)` still allows unbracketed IPv6 addresses
(distinguished from plain host-names by containing a `:`),
and `Uri.host` returns IPv6 addresses without brackets.
`Uri.parse` only accept IPv6 and IPvFuture in brackets.
(Only IPv6 can have a zone.)

Fixes #60483.

CoreLibraryReviewExempt: Local implementation only, no API.
Bug: https://dartbug.com/60483
Change-Id: Id369ba1316b34f443edfe5b0f56864c32beddccc
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/421081
Reviewed-by: Nate Bosch <nbosch@google.com>
Commit-Queue: Lasse Nielsen <lrn@google.com>

https://dart.googlesource.com/sdk/+/b2f0b8d08300af72c50bb0e566afe80aae891952
diff --git a/DEPS b/DEPS
index 861fd38..f0cef9c 100644
--- a/DEPS
+++ b/DEPS
@@ -238,7 +238,7 @@
 ]
 
 deps = {
-  'flutter/engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + 'af7f6393e6ba5923f7b425b2feaca35c0870fb36',
+  'flutter/engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + 'b2f0b8d08300af72c50bb0e566afe80aae891952',
 
   'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + '2249c4dbbfa479fc6a4fe351515c8afab2faf606',
 
diff --git a/commits.json b/commits.json
index 3a1475a..d63633c 100644
--- a/commits.json
+++ b/commits.json
@@ -1,4 +1,4 @@
 {
   "flutter":"2249c4dbbfa479fc6a4fe351515c8afab2faf606",
-  "flutter/engine/src/flutter/third_party/dart":"af7f6393e6ba5923f7b425b2feaca35c0870fb36"
+  "flutter/engine/src/flutter/third_party/dart":"b2f0b8d08300af72c50bb0e566afe80aae891952"
 }
\ No newline at end of file