BZ-1052313 - Restrictions on Number that is result of 'accumulate' CE are not shown in GRE when the rule is reopened

(cherry picked from commit 619b14877c5866212dec2efa1d72e2fe64fc07f2)
[BZ-1052313] fix drl unmarshalling of accumulate constraints

(cherry picked from commit 5b650c7ac5e64bb552746f7ccebbc37740b57518)
BZ-1052313 - Restrictions on Number that is result of 'accumulate' CE are not shown in GRE when the rule is reopened

(cherry picked from commit 5a38cb402d723af5bec833f9c155aecb5eaa2017)

Conflicts:
	drools-workbench-models/drools-workbench-models-commons/src/test/java/org/drools/workbench/models/commons/backend/rule/RuleModelDRLPersistenceUnmarshallingTest.java
[BZ-1052313] set bound variable name for accumulate pattern during drl unmarshalling

(cherry picked from commit 21dd2b8389b8645569aec77665fbb10c2c33f073)