Regression introduced with 83f77ab0661df992f241e5f9ecb1aa8f8eaeafec.
Interpreter errors are transported using NaN coded doubles, using simple
setNan()/isNan() to flag and ignore non-numeric values skips all error
values.
Change-Id: I0d3cb30262bc5ba7ee77e53a2bc45e56569fbc4b
see https://gerrit.libreoffice.org/#/c/3367/
and Change-Id: I00c96fa77d04b33a6f8c8cd3490dfcd9bdc9e84a for details
Change-Id: I199a75bc4042af20817265d5ef85b1134a96ff5a