[patch] Fix 2 bugs in crossing ways test (validator)

[bilbo]

I have attached patch that fixes two bugs in validator in crossing ways test:

1. ways tagged with layer=0 (default value for layer tag) are treated now the same as without layer tag. Before, way with layer=0 and second crossing way without the tag would not be detected as crossing.

2. ways tagged with landuse=reservoir are now also considered a "coastline", same as natural=water or natural=coastline, thus reporting crossing of reservoirs with other water bodies.

[bilbo]

Patch to fix those 2 bugs

[stoecker]

In [4048/josm]:

fix #6022 - better crossing way tests - patch by bilbo