[WIP] Zero padding on MemTiles #6207

Job	Run time
ubuntu-22.04 llvm assert=ON rtti=ON	9m 29s
ubuntu-22.04 llvm assert=ON rtti=OFF	9m 35s
ubuntu-22.04 llvm assert=OFF rtti=ON	9m 45s
ubuntu-22.04 llvm assert=OFF rtti=OFF	9m 42s
ubuntu-22.04 gcc assert=ON rtti=ON	10m 24s
ubuntu-22.04 gcc assert=ON rtti=OFF	10m 23s
ubuntu-22.04 gcc assert=OFF rtti=ON	10m 24s
ubuntu-22.04 gcc assert=OFF rtti=OFF	10m 24s
ubuntu-24.04 llvm assert=ON rtti=ON	9m 45s
ubuntu-24.04 llvm assert=ON rtti=OFF	9m 57s
ubuntu-24.04 llvm assert=OFF rtti=ON	9m 41s
ubuntu-24.04 llvm assert=OFF rtti=OFF	9m 38s
ubuntu-24.04 gcc assert=ON rtti=ON	10m 23s
ubuntu-24.04 gcc assert=ON rtti=OFF	10m 23s
ubuntu-24.04 gcc assert=OFF rtti=ON	10m 23s
ubuntu-24.04 gcc assert=OFF rtti=OFF	10m 23s
ubuntu-20.04 gcc-11 assert=ON rtti=OFF	9m 39s
ubuntu-20.04 gcc-11 assert=OFF rtti=OFF	9m 23s
ubuntu-20.04 gcc-11 assert=ON rtti=ON	9m 19s
ubuntu-20.04 gcc-11 assert=OFF rtti=ON	9m 35s
windows-2019 msvc assert=ON rtti=ON	10m 19s
windows-2019 msvc assert=ON rtti=OFF	10m 15s
windows-2019 msvc assert=OFF rtti=ON	10m 17s
windows-2019 msvc assert=OFF rtti=OFF	10m 17s
	3h 59m 43s

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