tests: refactor to use the new getlimits utility

tests: refactor to use the new getlimits utility

* tests/Coreutils.pm: Add function to make limits available
* tests/test-lib.sh: ditto
* tests/misc/join: Check for both SIZE_OFLOW and UINTMAX_OFLOW
rather than using arbitrary 2^128
* tests/misc/sort: ditto
* tests/misc/uniq: ditto
* tests/misc/printf: Check for both INT_OFLOW and INT_UFLOW
rather than using arbitrary -2^31
* tests/misc/seq-long-double: Check for INTMAX_OFLOW
rather than using arbitrary 2^63
* tests/misc/split-fail: Check --lines --bytes and --line-bytes
options limits on all platforms. Note getlimits obviates the
need to use expr to check if 32 bit integers are supported,
which I think was invalid anyway as expr now supports bignum?
* tests/misc/test: Check for UINTMAX_OFLOW rather than
using arbitrary 2^64 and 2^128. Check for INTMAX_UFLOW
rather than using arbitrary -2^64
* tests/misc/timeout-parameters: Check for UINT_OFLOW
rather than using arbitrary 2^32
* tests/misc/truncate-overflow: Don't depend on truncate
to determine if we're on a 32 or 64 bit platform and
instead use the various OFF_T limits
* tests/misc/sort-merge: Check for UINTMAX_OFLOW
rather than using arbitrary 2^64+1
* tests/misc/unexpand: ditto