Bound inserted-sequence suffix comparisons

[justinblethrow-cloud]

Summary

• Bound inserted-sequence suffix comparisons by the allocated sequence buffer.
• Interpret genomeSuffixLengthMax as a number of bases, consistently with genome generation.
• Stop comparisons at the genome spacing sentinel and return equality for self-comparisons.
• Add a focused ASan/UBSan regression test.

Problem

Runtime sequence insertion (alignReads --genomeFastaFiles ...) passes the default unlimited suffix length into this comparator. On 2.7.11b, the caller divides that value by sizeof(uint64_t) and memcmp receives 2,305,843,009,213,693,951 bytes. ASan aborts in funCompareUintAndSuffixesMemcmp; the comparator also returns a nonzero result when given the same element twice.

Validation

• extras/tests/scripts/testSuffixComparator.sh passes with ASan/UBSan; the same test against unmodified 2.7.11b fails in memcmp.
• A full STAR build succeeds.
• Runtime sequence insertion with the default suffix-length setting completes under ASan.
• Resulting SAM records are byte-identical to mapping against the equivalent prebuilt index.