Set block-size for XZ mini-debug-info compression.

This allows the compression to be done on multiple threads
and more importantly, it allows libunwindstack to decompress
only the needed blocks, which reduces unwind time and memory.

Bug: 110133331
Test: verify lazy decompression in libunwindstack
Change-Id: Ia3f597928edcbc85acdf05cb5c83ac7fced39148