Use SFTDenseChunkMap on 64bits when vm_space is enabled

[qinsoon]

This PR resolves the issues found in mmtk/mmtk-julia#143.

[2024-03-19T05:23:33Z INFO  mmtk::policy::vmspace] Set [78624DC00000, 786258000000) as VM region (heap available range [20000000000, 220000000000))
thread '<unnamed>' panicked at 'start = 78624DC00000 + bytes = 171966464 should be smaller than space_start 380000000000 + max extent 2199023255552, index 28, table size 31', /home/runner/.cargo/git/checkouts/mmtk-core-89cdc7bf360cce7f/46b0abe/src/policy/sft_map.rs:202:21
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
fatal runtime error: failed to initiate panic, error 5

Basically we should not use SFTSpaceMap when we have off-heap memory. Julia tries to set VM space at an address range outside our heap range, and that causes issues when we compute index for SFTSpaceMap. Using SFTDenseChunkMap will solve the issue.

Changes:

• Use SFTDenseChunkMap if vm_space is enabled.
• Add a range check for SFTSpaceMap::has_sft_entry(). The address/index computation is only correct if the address is in the range.
• Add a simple test case for Check the assertion failure in SFT map mmtk-julia#143.

[k-sareen]

I presume 32-bit compressed pointer VMs are unaffected? (Selfish question given ART is 32-bit and has a bootimage)

[qinsoon]

I presume 32-bit compressed pointer VMs are unaffected? (Selfish question given ART is 32-bit and has a bootimage)

Right, 32 bits are not affected. I will update the title to make it clearer.

[wks]

LGTM, but this PR needs rebasing.