enabling 32-X-64 testing on 64-bit systems

[Andrew Cagney <cagney@redhat.com>]

[from meeting]

At present the 32-on-64 tests tests are disabled, the suggestion is to 
enable them.

More exactly, on a 64-bit system, there are the following combinations:

- 64-bit funit run full test-suite using 64-bit target program binaries

- 64-bit funit run full test-suite using 32-bit target program binaries

- 32-bit funit run full test-suite using 32-bit target program binaries

within each of those test runs, there is a collection of 32-on-64 
specific tests such as:

- track a 32-bit process exec-ing a 64-bit process

except for the 64-bit funit using 32-bit target program case, those 
tests are currently skipped (untested).

The rationale was that the 32-bit target programs may not be present, so 
disabling the tests by default prevented misleading results (e.g., only 
a 64-bit frysk being installed).

The disadvantage is, as MJW observed, that people are not generally 
aware of these tests and so don't run them.

The intent is to reverse this situtation: enable the 32-on-64 tests when 
ever possible; requiring an explicit option to disable them