We need better way of handling inner- and outer- loop tests

[krwq]

Some tests (especially slow tests) do not belong to the idea of inner loop tests (aka unit tests).
We should have a consistent way of deciding which are inner and which are outer loop tests.

List of disabled tests (XPath.XDocument):
AttributeSpecifiedTest
AxesCombinationsTest2104
AxesCombinationsTest2155
AxesCombinationsTest2201
AxesCombinationsTest2202
AxesCombinationsTest2205
AxesCombinationsTest2206
AxesCombinationsTest2208
AxesCombinationsTest2210
AxesCombinationsTest2211
AxesCombinationsTest2214
AxesCombinationsTest2220
AxesCombinationsTest23
AxesCombinationsTest232
AxesCombinationsTest233
AxesCombinationsTest24
AxesCombinationsTest240
AxesCombinationsTest248
AxesCombinationsTest262
AxesCombinationsTest264
AxesCombinationsTest265
AxesCombinationsTest266
AxesCombinationsTest268
AxesCombinationsTest288
AxesCombinationsTest289
AxesCombinationsTest290
AxesTest1271
AxesTest1272
BooleanFunctionsTest2518
ComplexExpressionsTest312
ComplexExpressionsTest319
ComplexExpressionsTest32
ComplexExpressionsTest320
ComplexExpressionsTest321
ComplexExpressionsTest324
ComplexExpressionsTest329
ComplexExpressionsTest330
ComplexExpressionsTest331
ComplexExpressionsTest337
ComplexExpressionsTest340
ComplexExpressionsTest523
ComplexExpressionsTest53
ComplexExpressionsTest54
ComplexExpressionsTest56
GlobalizationTest566
LongElementName
MatchesTest1164
MatchesTest1167
PredicatesTest1072
UsingPositionFunctionTest663