Increase tol error on palm4msa lambda to pass two tests both on Windows and Linux.

The approximation is good anyway with these lambdas so the tests shouldn't fail.
The two tests are: MATFILE_FACT_MEG_double and MATFILE_FACT_MEG_TRANSPOSED_double.
See also https://cdash-ci.inria.fr/viewTest.php?onlyfailed&buildid=66551.