Extend WebUI test_pwpolicy suite with the following test cases

Added tests:
krbpwdminlength: lower range integer
krbmaxpwdlife: non-integer, abc
krbmaxpwdlife: upper range integer,2147483648
krbmaxpwdlife: lower range integer,-1
krbminpwdlife: non-integer,edf
krbminpwdlife: upper range integer,2147483648
krbminpwdlife: lower range integer,-1
krbpwdhistorylength: non-integer,HIJ
krbpwdhistorylength: upper range integer,2147483648
krbpwdhistorylength: lower range integer,-1
krbpwdmindiffchars: noon-integer,3lm
krbpwdmindiffchars: upper range integer,2147483648
krbpwdmindiffchars: lower range integer, -1
krbpwdminlength: non-integer, n0p
krbpwdminlength: upper range integer,2147483648
krbpwdminlength: lower range integer, -1
cospriority: non-integer, abc
cospriority: upper range integer,2147483648
cospriority: lower range integer,-1
krbpwdmaxfailure: non-integer
krbpwdmaxfailure: upper range integer
krbpwdmaxfailure: lower range integer
krbpwdfailurecountinterval: non-integer
krbpwdfailurecountinterval: upper range integer
krbpwdfailurecountinterval: lower range integer
krbpwdlockoutduration: non-integer
krbpwdlockoutduration: upper range integer
krbpwdlockoutduration: lower range integer
deletePolicy_with various scenario
MeasurementUnitAdded_Bug798363
Delete global password policy
add_Policy_adder_dialog_bug910463
delete_Policy_deleter_dialog_bug910463
test field: cospriority
modifyPolicy(undo/refresh/reset)
empty policy name
upper bound of data range
lower bound of data range
non integer for policy priority