fix TestValidTerminalMode: missing output from echo SHELL $SHELL

add leading `echo` to have better compatibility

before

```
 go test -run ^TestValidTerminalMode -v
=== RUN   TestValidTerminalMode
    session_test.go:261: echo SHELL $SHELL && stty -a && exit:
        Last login: Thu Jul  6 12:24:38 2023 from 192.168.200.1
SHELL /bin/bashubuntu:~$
        speed 38400 baud; rows 80; columns 40;
        line = 0;
        intr = ^C; quit = ^\; erase = ^?;
        kill = ^U; eof = ^D; eol = <undef>;
        eol2 = <undef>; swtch = <undef>;
        start = ^Q; stop = ^S; susp = ^Z;
        rprnt = ^R; werase = ^W; lnext = ^V;
        discard = ^O; min = 1; time = 0;
        -parenb -parodd -cmspar cs8 -hupcl
        -cstopb cread -clocal -crtscts
        -ignbrk -brkint -ignpar -parmrk -inpck
        -istrip -inlcr -igncr icrnl ixon -ixoff
        -iuclc -ixany -imaxbel -iutf8
        opost -olcuc -ocrnl onlcr -onocr -onlret
        -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
        isig icanon iexten -echo echoe echok
        -echonl -noflsh -xcase -tostop -echoprt
        echoctl echoke -flusho -extproc
        logout
    session_test.go:266: missing output from echo SHELL $SHELL
```

after

```
 go test -run ^TestValidTerminalMode -v
=== RUN   TestValidTerminalMode
    session_test.go:261: echo SHELL $SHELL && stty -a && exit:
        Last login: Thu Jul  6 12:24:38 2023 from 192.168.200.1
        bolian@ubuntu:~$
        SHELL /bin/bash
        speed 38400 baud; rows 80; columns 40;
        line = 0;
        intr = ^C; quit = ^\; erase = ^?;
        kill = ^U; eof = ^D; eol = <undef>;
        eol2 = <undef>; swtch = <undef>;
        start = ^Q; stop = ^S; susp = ^Z;
        rprnt = ^R; werase = ^W; lnext = ^V;
        discard = ^O; min = 1; time = 0;
        -parenb -parodd -cmspar cs8 -hupcl
        -cstopb cread -clocal -crtscts
        -ignbrk -brkint -ignpar -parmrk -inpck
        -istrip -inlcr -igncr icrnl ixon -ixoff
        -iuclc -ixany -imaxbel -iutf8
        opost -olcuc -ocrnl onlcr -onocr -onlret
        -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
        isig icanon iexten -echo echoe echok
        -echonl -noflsh -xcase -tostop -echoprt
        echoctl echoke -flusho -extproc
        logout
--- PASS: TestValidTerminalMode (0.06s)
```

Change-Id: If60c040edb8c78a7d86bf58a6be47636d9e8f173
GitHub-Last-Rev: a2cc1b1af09e47df82fcb8685d829dfed945e8b0
GitHub-Pull-Request: golang/crypto#264
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/508115
Reviewed-by: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Heschi Kreinick <heschi@google.com>
Auto-Submit: Heschi Kreinick <heschi@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
1 file changed
tree: 49c96a93dfd9002ecb506595d094ff07c9a38ff4
  1. acme/
  2. argon2/
  3. bcrypt/
  4. blake2b/
  5. blake2s/
  6. blowfish/
  7. bn256/
  8. cast5/
  9. chacha20/
  10. chacha20poly1305/
  11. cryptobyte/
  12. curve25519/
  13. ed25519/
  14. hkdf/
  15. internal/
  16. md4/
  17. nacl/
  18. ocsp/
  19. openpgp/
  20. otr/
  21. pbkdf2/
  22. pkcs12/
  23. poly1305/
  24. ripemd160/
  25. salsa20/
  26. scrypt/
  27. sha3/
  28. ssh/
  29. tea/
  30. twofish/
  31. x509roots/
  32. xtea/
  33. xts/
  34. .gitattributes
  35. .gitignore
  36. codereview.cfg
  37. CONTRIBUTING.md
  38. go.mod
  39. go.sum
  40. LICENSE
  41. PATENTS
  42. README.md
README.md

Go Cryptography

Go Reference

This repository holds supplementary Go cryptography libraries.

Download/Install

The easiest way to install is to run go get -u golang.org/x/crypto/.... You can also manually git clone the repository to $GOPATH/src/golang.org/x/crypto.

Report Issues / Send Patches

This repository uses Gerrit for code changes. To learn how to submit changes to this repository, see https://golang.org/doc/contribute.html.

The main issue tracker for the crypto repository is located at https://github.com/golang/go/issues. Prefix your issue with “x/crypto:” in the subject line, so it is easy to find.

Note that contributions to the cryptography package receive additional scrutiny due to their sensitive nature. Patches may take longer than normal to receive feedback.