Fold rcv_test into tcp_test

This prevents go module errors of the form
 found packages tcp (accept.go) and rcv (rcv_test.go) in ...

PiperOrigin-RevId: 398370042

pkg/tcpip/transport/tcp/BUILD

@@ -80,9 +80,10 @@ go_library(
 
 go_test(
     name = "tcp_x_test",
-    size = "medium",
+    size = "large",
     srcs = [
         "dual_stack_test.go",
+        "rcv_test.go",
         "sack_scoreboard_test.go",
         "tcp_noracedetector_test.go",
         "tcp_rack_test.go",
@@ -113,16 +114,6 @@ go_test(
     ],
 )
 
-go_test(
-    name = "rcv_test",
-    size = "small",
-    srcs = ["rcv_test.go"],
-    deps = [
-        "//pkg/tcpip/header",
-        "//pkg/tcpip/seqnum",
-    ],
-)
-
 go_test(
     name = "tcp_test",
     size = "small",

pkg/tcpip/transport/tcp/rcv_test.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package rcv_test
+package tcp_test
 
 import (
 	"testing"