Update test cert generation scripts to use SHA-256 by default

Update test cert generation scripts to use SHA-256 by default

This cleans up the README file to clearly indicate which certificates are real world certificates, which are generated by hand / by other sources, and which are generated via script (and which script).

Additionally, several test certificates that were previously generated by hand and several test CRLSets that were hardcoded are now generated automatically by the scripts.

BUG=401365
Committed: https://crrev.com/04b34e02245194b01c08cd5cfb350378797e8681
Cr-Commit-Position: refs/heads/master@{#297047}

[Ryan Sleevi, 2014-08-28 04:06:24]

rsleevi@chromium.org changed reviewers:
+ wtc@chromium.org

[Ryan Sleevi, 2014-08-28 04:06:24]

wtc: You game for reviewing this? I can pass it off to David or Adam if you'd
prefer.

[wtc, 2014-08-28 21:28:10]

Patch set 1 LGTM.

1. The CL's description should also describe the other changes in this CL. The
scripts are modified to generate several other certificates.

2. I think it's better to run the updated scripts and check in the new
certificates at the same time to keep the scripts and generated certificates in
sync.

[Ryan Sleevi, 2014-08-28 21:32:06]

On 2014/08/28 21:28:10, wtc wrote:
> Patch set 1 LGTM.
> 
> 1. The CL's description should also describe the other changes in this CL. The
> scripts are modified to generate several other certificates.
> 
> 2. I think it's better to run the updated scripts and check in the new
> certificates at the same time to keep the scripts and generated certificates
in
> sync.

Because it requires updating the tests (and expectations) I split that into
https://codereview.chromium.org/515813002/

[Ryan Sleevi, 2014-09-26 20:04:59]

The CQ bit was checked by rsleevi@chromium.org

[commit-bot: I haz the power, 2014-09-26 20:06:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/515583004/20001

[commit-bot: I haz the power, 2014-09-26 20:10:19]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-09-26 20:10:20]

Try jobs failed on following builders:
  linux_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/linux_gpu/builds/...)
  mac_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/mac_gpu/builds/61386)
  win_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu/builds/66252)
  android_aosp on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/android_aosp/bu...)
  android_arm64_dbg_recipe on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/android_arm64_d...)
  android_chromium_gn_compile_dbg on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/android_chromiu...)
  android_chromium_gn_compile_rel on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/android_chromiu...)
  android_clang_dbg_recipe on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/android_clang_d...)
  chromium_presubmit on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)
  linux_chromium_gn_dbg on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_gn_rel on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  ios_dbg_simulator on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_dbg_simulator...)
  ios_rel_device on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_rel_device/bu...)
  ios_rel_device_ninja on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_rel_device_ni...)
  mac_chromium_compile_dbg on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_swarming on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)
  win8_chromium_rel on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win8_chromium_rel...)
  win_chromium_x64_rel_swarming on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[Ryan Sleevi, 2014-09-26 20:47:10]

The CQ bit was checked by rsleevi@chromium.org

[commit-bot: I haz the power, 2014-09-26 20:48:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/515583004/40001

[commit-bot: I haz the power, 2014-09-26 22:03:13]

Committed patchset #3 (id:40001) as 67e84d4fea44c3c00df287556909069d7886579f

[commit-bot: I haz the power, 2014-09-26 22:03:51]

Patchset 3 (id:??) landed as
https://crrev.com/04b34e02245194b01c08cd5cfb350378797e8681
Cr-Commit-Position: refs/heads/master@{#297047}