Tiny Corsica invalid vertex position

[bb]

in r19444 the seeds 8776 and 4533 the loading of tiny corsica in Atlas fails with:

ERROR: JavaScript error: uncaught exception: getHeight: invalid vertex position (-6, 70)
ERROR: CMapGeneratorWorker::Run: Failed to load RMS 'maps/random/corsica.js'
WARNING: JavaScript warning: Script value conversion check failed: v.isNumber() (got type undefined)

(the values in getHeights can vary a bit)

This error was also present in A21, but at other seeds f.e. 7125 (tiny)

[elexis]

The error has probably been in there since the beginning of the map and probably only applies to tiny maps.

It's for-loop after var nbBeaches = scaleByMapSize(2,5); that creates the beach where players can build docks, specifically straightPassageMaker(startX, startZ,endX,endZ, 25, 18, 4,clShore,null);

I've posted the patch that fixes it to ​https://code.wildfiregames.com/D384 There are still other things wrong with tiny maps on corsica, since the map wasn't exactly designed for that mapsize, but if people want to go for that map, they should be able to succeed the mapgen.

[elexis]

In 19461:

Fix beach painting on the Corsica vs Sardinia map that broke everything on tiny sizes.

Differential Revision: ​https://code.wildfiregames.com/D384
Fixes #4531
Reviewed By: bb