tests: add hghave rule 'setprocname' to check if osutil.setprocname and use it

setprocname is not present when we build a pure version. This leads to output
changes in test-chg.t

This should make test suite green on Python 2 pure build with chg.

Differential Revision: https://phab.mercurial-scm.org/D8638

tests/hghave.py

@@ -683,6 +683,17 b' def has_serve():'
     return True
 
 
+@check("setprocname", "whether osutil.setprocname is available or not")
+def has_setprocname():
+    try:
+        from mercurial.utils import procutil
+
+        procutil.setprocname
+        return True
+    except AttributeError:
+        return False
+
+
 @check("test-repo", "running tests from repository")
 def has_test_repo():
     t = os.environ["TESTDIR"]

tests/test-chg.t

@@ -229,13 +229,13 b' check that server events are recorded:'
   server.log.1
 
 print only the last 10 lines, since we aren't sure how many records are
-preserved (since setprocname isn't available on py3, the 10th-most-recent line
-is different when using py3):
+preserved (since setprocname isn't available on py3 and pure version,
+the 10th-most-recent line is different when using py3):
 
   $ cat log/server.log.1 log/server.log | tail -10 | filterlog
-  YYYY/MM/DD HH:MM:SS (PID)> confighash = ... mtimehash = ... (py3 !)
+  YYYY/MM/DD HH:MM:SS (PID)> confighash = ... mtimehash = ... (no-setprocname !)
   YYYY/MM/DD HH:MM:SS (PID)> forked worker process (pid=...)
-  YYYY/MM/DD HH:MM:SS (PID)> setprocname: ... (no-py3 !)
+  YYYY/MM/DD HH:MM:SS (PID)> setprocname: ... (setprocname !)
   YYYY/MM/DD HH:MM:SS (PID)> received fds: ...
   YYYY/MM/DD HH:MM:SS (PID)> chdir to '$TESTTMP/extreload'
   YYYY/MM/DD HH:MM:SS (PID)> setumask 18