Revert of chromium_tests: raise infra failure when no compile targets are specified

Revert of chromium_tests: raise infra failure when no compile targets are specified (patchset #1 id:1 of https://codereview.chromium.org/1376453002/ )

Reason for revert:
This is not a valid assumption, e.g. the clang bots all use the empty compile target as build target and were all broken with this. (As discussed previously, even!)

Original issue's description:
> chromium_tests: raise infra failure when no compile targets are specified
> 
> This relies on default compile targets either on the recipe side or ninja,
> but breaks badly with e.g. analyze. We're trying to make as much of bot
> config explicit as possible.
> 
> BUG=536186
> 
> Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=296903

TBR=tandrii@chromium.org,sergiyb@chromium.org,hans@chromium.org,phajdan.jr@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=536186

[Nico, 2015-09-28 18:13:59]

Created Revert of chromium_tests: raise infra failure when no compile targets
are specified

[commit-bot: I haz the power, 2015-09-28 18:15:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1377453003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1377453003/1

[commit-bot: I haz the power, 2015-09-28 18:15:35]

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

[commit-bot: I haz the power, 2015-09-28 18:15:39]

Failed to apply patch for scripts/slave/recipe_modules/chromium_tests/api.py:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  patching file scripts/slave/recipe_modules/chromium_tests/api.py
  Hunk #1 FAILED at 447.
  1 out of 1 hunk FAILED -- saving rejects to file
scripts/slave/recipe_modules/chromium_tests/api.py.rej

Patch:       scripts/slave/recipe_modules/chromium_tests/api.py
Index: scripts/slave/recipe_modules/chromium_tests/api.py
diff --git a/scripts/slave/recipe_modules/chromium_tests/api.py
b/scripts/slave/recipe_modules/chromium_tests/api.py
index
b3cd8b0af92c0a84ee97b7e5a56f44ffe76639e8..39038f6fd1f69e472604bd6cea182ef5e272f0fd
100644
--- a/scripts/slave/recipe_modules/chromium_tests/api.py
+++ b/scripts/slave/recipe_modules/chromium_tests/api.py
@@ -447,8 +447,6 @@
                              isolated_targets=isolated_targets,
                              name='generate_build_files%s' % name_suffix)
 
-    if not compile_targets:
-      raise self.m.step.InfraFailure('Misconfigured bot: no compile targets')
     self.m.chromium.compile(compile_targets, name='compile%s' % name_suffix)
 
   def tests_for_builder(self, mastername, buildername, update_step,
master_dict,

[Nico, 2015-09-28 18:56:28]

manually landed revert in https://codereview.chromium.org/1372133003

[Sergiy Byelozyorov, 2015-09-29 07:30:18]

lgtm