Bug 904952

Description of problem
----------------------
For a simple process with expects another message after an instance has been created the signal can be made just once. In case another instance is created then the attempt to signal will fail with a 

StaleObjectStateException: Row was updated or deleted by another transaction. 

Looks like the issue is related to the method:
public Environment getEnvironment(Map<String, Object> overrides);

This method creates a new Environment each time it's called which seems to be the source of the problem.


How reproducible
----------------
Use the attached quickstart.


Steps to Reproduce
------------------
1. ant deploy
2. ant runtest (first run is OK)
3. ant runtest (second run will FAIL)
  
Actual results: output from steps to reproduce 2 and 3
------------------------------------------------------
##### Starting process: 
[Empty].
Hello 1: Laurel
##### Process started: 
[Empty]
##### Signalling process: 
[Empty]
Hello 2: Hardy
##### Process signalled:

##### Starting process: 
[Empty].
Hello 1: Laurel
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect)


Expected results: output from steps to reproduce 2 and 3
--------------------------------------------------------
##### Starting process: 
[Empty].
Hello 1: Laurel
##### Process started: 
[Empty]
##### Signalling process: 
[Empty]
Hello 2: Hardy
##### Process signalled:

##### Starting process: 
[Empty].
Hello 1: Laurel
##### Process started: 
[Empty]
##### Signalling process: 
[Empty]
Hello 2: Hardy
##### Process signalled: