Steps to reproduce:

* Build with `integer` sanitizer
* Start: `UBSAN_OPTIONS="suppressions=$(pwd)/test/sanitizer_suppressions/ubsan:print_stacktrace=1:halt_on_error=1:report_error_type=1" ./src/qt/bitcoin-qt -chain=main`
* Enter `getdescriptorinfo "sh(multi(1,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,[00000000]xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/58)0)"` into the console
cls = cls * 3 + (pos >> 5); 
        if (++clscount == 3) {
            
            c = PolyMod(c, cls);
            cls = 0;
            clscount = 0;
        }
    }
    if (clscount > 0) c = PolyMod(c, cls);
    for (int j = 0; j < 8; ++j) c = PolyMod(c, 0); 
    c ^= 1; 
    std::string ret(8, ' ');
    for (int j = 0; j < 8; ++j) ret[j] = CHECKSUM_CHARSET[(c >> (5 * (7 - j))) & 31];
    return ret;
}
std::string AddChecksum(const std::string& str) { return str + "#" + DescriptorChecksum(str); }
typedef std::vector<uint32_t> KeyPath;
struct PubkeyProvider
{
protected:
    
    
    uint32_t m_expr_index;
public:
    explicit PubkeyProvider(uint32_t exp_index) : m_expr_index(exp_index) {}
    virtual ~PubkeyProvider() = default;
    /** Compare two public keys represented by this provider.
     * Used by the Miniscript descriptors to check for duplicate keys in the script.
     */
    bool operator<(PubkeyProvider& other) const {