murmurhash32 ubsan fix.

[amosbird]

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Can be reproduced with ubsan build and following queries.

SELECT * from numbers(1000, 2) where murmurHash2_32(toString(number)) = 1;
SELECT * from numbers(1000, 2) where murmurHash3_32(toString(number)) = 1;

For changelog. Remove if this is non-significant change.

Category (leave one):

• Bug Fix