Fix string multiplication with a value between 0.0 and 1.0

This commit fixes a regression of 6306ac8966.

tests/jq.test

@@ -1284,6 +1284,10 @@ indices(", ")
 ["a", "ab", "abc"]
 ["aaa", "ababab", "abcabcabc"]
 
+[.[] * "abc"]
+[-1.0, -0.5, 0.0, 0.5, 1.0, 1.5, 3.7, 10.0]
+[null,null,null,"abc","abc","abc","abcabcabc","abcabcabcabcabcabcabcabcabcabc"]
+
 [.[] / ","]
 ["a, bc, def, ghij, jklmn, a,b, c,d, e,f", "a,b,c,d, e,f,g,h"]
 [["a"," bc"," def"," ghij"," jklmn"," a","b"," c","d"," e","f"],["a","b","c","d"," e","f","g","h"]]