VALGRIND_DISABLE_ADDR_ERROR_REPORTING_IN_RANGE and
VALGRIND_ENABLE_ADDR_ERROR_REPORTING_IN_RANGE
and supporting machinery for managing whole-address-space sparse
mappings. n-i-bz. In support of
https://bugzilla.mozilla.org/show_bug.cgi?id=970643
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13884