Bug 620: fix robustness issue in JacobiSVD::solve (also fix a perf. issue)
(transplanted from afff5b36628a642ad0bc1da1efadb7d1c41da3f4)

--HG--
branch : 3.1
extra : transplant_source : %AF%FF%5B6b%8Ad%2A%D0%BC%1D%A1%EF%AD%B7%D1%C4%1D%A3%F4