Re-enabled zztest_max_digits10 test to check on RaspberryPI failures in constants_eg1.cpp.

git-svn-id: http://svn.boost.org/svn/boost/trunk@83597 b8fc166d-592f-0410-95f2-cb63ce0dd405
Revised zztest_max_digits10 test to check on RaspberryPI failures in constants_eg1.cpp.

git-svn-id: http://svn.boost.org/svn/boost/trunk@83598 b8fc166d-592f-0410-95f2-cb63ce0dd405