...which has become necessary since bd60d411
"Handle oveflow in O(U)String::toInt() functions" reduces values in the range
(SAL_MAX_INT32 .. SAL_MAX_UINT32] to zero, but some calls of toInt32(16) relied
on getting a correct (unsigned) value for the whole input range ["0" ..
"FFFFFFFF"] (see libreoffice-4-1 commit 9bf6c833
"Revert overflow checks in O[U]String::toInt{32,64} again").

Audited all uses of toInt32/64 with non-decimal radix.  (There is still a TODO
comment in oox/source/helper/attributelist.cxx, and
stoc/source/typeconv/convert.cxx will still need some love and test code.)

Change-Id: Iadaca1c0e41dab553687d0ce41c20c10cd657a95