Tests: unit_stop() removed where possible.

Since wait_for_record() was introduced there is no need
to stop Unit before parsing unit.log.

test/test_python_application.py

@@ -5,7 +5,6 @@ import time
 
 import pytest
 
-from conftest import unit_stop
 from unit.applications.lang.python import TestApplicationPython
 from unit.option import option
 
@@ -157,8 +156,6 @@ custom-header: BLAH
 
         self.conf({"listeners": {}, "applications": {}})
 
-        unit_stop()
-
         assert (
             self.wait_for_record(r'RuntimeError') is not None
         ), 'ctx iter atexit'
@@ -337,8 +334,6 @@ Connection: close
 
         self.conf({"listeners": {}, "applications": {}})
 
-        unit_stop()
-
         assert self.wait_for_record(r'At exit called\.') is not None, 'atexit'
 
     def test_python_process_switch(self):
@@ -496,8 +491,6 @@ last line: 987654321
 
         self.get()
 
-        unit_stop()
-
         assert (
             self.wait_for_record(r'\[error\].+Error in application\.')
             is not None
@@ -537,8 +530,6 @@ last line: 987654321
 
         self.get()
 
-        unit_stop()
-
         assert self.wait_for_record(r'Close called\.') is not None, 'close'
 
     def test_python_application_close_error(self):
@@ -546,8 +537,6 @@ last line: 987654321
 
         self.get()
 
-        unit_stop()
-
         assert (
             self.wait_for_record(r'Close called\.') is not None
         ), 'close error'
@@ -557,8 +546,6 @@ last line: 987654321
 
         self.get()
 
-        unit_stop()
-
         assert (
             self.wait_for_record(
                 r'\[error\].+the application returned not an iterable object'