fix(terrain): Port merged TheSuperHackers map and terrain fixes

[tintinhamans]

Ports three merged upstream fixes for crashes and leaks when loading maps and drawing rivers. Each is a cherry-pick -x of the upstream commit.

• bugfix(w3dwater): Skip rivers that overflow the dynamic index buffer TheSuperHackers/GeneralsGameCode#3489 bugfix(w3d): Skip rivers that overflow the dynamic index buffer
• fix(worldheightmap): Free the legacy cliff state buffer when loading blend tile data TheSuperHackers/GeneralsGameCode#3482 fix(worldheightmap): Free the legacy cliff state buffer when loading blend tile data
• bugfix(worldheightmap): Reject map sizes that overflow the cell array allocations TheSuperHackers/GeneralsGameCode#3486 bugfix(worldheightmap): Reject map sizes that overflow the cell array allocations

MapReaderWriterInfo.h exists once per game here, so TheSuperHackers#3486 is applied to both the Generals and GeneralsMD copies. The rest is in Core.

Zero Hour (z_generals) builds here. The Generals copy of MapReaderWriterInfo.h was not compiled, g_generals does not build on this branch.