tool: fix memory ranges overlapping checks

[dreamliner787-9]

Previously, ranges_overlap() in util.rs returns true if two inclusive ranges overlap. But builder.rs was passing half-open ranges which caused the tool to report that two memory regions are overlapping when in reality they were not.

This PR changed ranges_overlap() to work on half-open ranges instead.

An example that replicated the bug:

<system>
    <memory_region name="mr" size="0x1000" />
    <protection_domain name="x86_64_ioport" priority="100" >
        <program_image path="x86_64_ioport.elf" />

        <!-- The executable ELF segment will always be placed at 0x200000 by libmicrokit linker script
        So if we put a 0x1000 bytes memory region at 0x1ff000, the tool must not report any errors -->
        <map mr="mr" perms="rw" vaddr="0x1ff000" />
    </protection_domain>
</system>

% ./microkit bug.system --search-path build --board x86_64_generic --config debug -o build/initialiser.elf -r build/report.txt
Error: "ERROR: mapping MR 'mr' to PD 'x86_64_ioport' with vaddr [0x1ff000..0x200000) will overlap with an ELF segment at [0x200000..0x201000)"

[midnightveil]

given that al of the usercases of this function give it exclusive ranges... maybe this should be changed?

or do we always tend to use inclusive ranges

[dreamliner787-9]

That's reasonable, I will change it like you suggested