Enable most dart:io tests on Windows

tests/standalone/standalone.status

Index: tests/standalone/standalone.status
diff --git a/tests/standalone/standalone.status b/tests/standalone/standalone.status
index dd85bd4849ba1b62772fdedeb885957060949a26..552fea4b7d77603ed69864d65b264fd5799035f7 100644
--- a/tests/standalone/standalone.status
+++ b/tests/standalone/standalone.status
@@ -17,14 +17,6 @@ io/secure_server_client_certificate_test: Fail
 
 [ $runtime == vm && ( $system == windows ) ]
 io/raw_server_socket_cancel_test: Pass, Fail, Timeout # Issue 8675
-io/socket_test: Pass, Timeout # Issue 8676
-io/socket_exception_test: Pass, Timeout # Issue 8677
-io/http_client_request_test: Pass, Fail # Issue 8681
-io/http_proxy_test: Pass, Timeout # Issue 7773
-io/https_client_certificate_test: Pass, Timeout # Issue 8674
-io/https_client_socket_reuse_test: Pass, Timeout # Issue 8674
-io/https_server_test: Pass, Timeout # Issue 8674
-io/web_socket_test: Pass, Fail, Timeout # Issue 8824
 
 [ $runtime == vm ]
 package/package_isolate_test: Fail # http://dartbug.com/7520.