Add a new flag '--with-test-suite' to configure to control whether
the test suite binaries are built by default. ie built with a
plain 'make', as opposed to delayed until 'make check'

For builds from tar.gz tests will not be built by default. For
builds from GIT, tests with be on by default, to try and ensure
that patch developers don't accidentally break the test suites
without noticing.

* configure.ac: Add --with-test-suite
* tests/Makefile.am: Use noinst_PROGRAMS instead of check_PROGRAMS
  if building tests by default. Consolidate setting of TESTS and
  {noinst,check}_PROGRAMS to avoid duplication