net/http: skip TestLinuxSendfile on mips64 for now

See issues for details. We can expand this test during the Go 1.9
cycle.

Updates #18008

Change-Id: I78b6b7e8dede414769be97898e29f969bc2a9651
Reviewed-on: https://go-review.googlesource.com/33430Reviewed-by: Cherry Zhang <cherryyz@google.com>

src/net/http/fs_test.go

@@ -1091,9 +1091,7 @@ func TestLinuxSendfile(t *testing.T) {
 		// and will error out if we specify that with `-e trace='.
 		syscalls = "sendfile"
 	case "mips64":
-		// TODO: minimize this set once golang.org/issue/18008
-		// is understood.
-		syscalls = "network,file"
+		t.Skip("TODO: update this test to be robust against various versions of strace on mips64. See golang.org/issue/33430")
 	}
 
 	var buf bytes.Buffer