If faultinjector is not enabled during configuration, this patch
identifies tests that use faultinjector and excludes them from running.
A new option "--exclude-file" is added to pg_regress.  It specifies a
file having names of tests, one per line, to be excluded from running.

The global makefile is changed so that the exclude file creation and
adding the --exclude-file option to pg_regress (and
pg_isolation*regress) command line is taken care of automatically.
However, one must perform these actions manually if pg_regress needs to
be directly invoked from command line (instead of a make target).
Running tests with faultinjector disabled is not a common developer
workflow, so this should be acceptable.

The advantage of changing global makefile is that all test frameworks
that are based on pg_regress, such as isolation and also contrib modules
need no change to their makefiles.  For example, if one creates a
isolation test with faultinjector, simply add it to the right schedule,
it will automatically be excluded from running when faultinjector is not
enabled.