to make the common access pattern cache friendly.

For example, in case of a large sum like =SUM(A1:A50000)
where the column A itself is composed of formulas, the inner
loop of computation involves accessing ScFormulaResult's of
each formulacell of column A. Recently this was made faster
by the use of a "cache" flag (commit 77f7b476), so to get
the result it just need access to the cache bool-flag and the
mfValue member. Hence it makes sense to group the bools
together with the mfValue member.

Change-Id: If12d0736ba98b9d74e7b96304fce71e8e6e66619
Reviewed-on: https://gerrit.libreoffice.org/63063
Tested-by: Jenkins
Reviewed-by: Dennis Francis <dennis.francis@collabora.com>