units: suppress the error report of shell itself

When ctags is crashed, the shell process running the
ctags process reports the crash:

    Testing verilog-sv-nocontext misc/units: line 203: \
    14080 Segmentation fault ${_CMDLINE} 2> "${ostderr}" > "${orawout}" \
    failed (unexpected exit status: 139)

This report disturbs the well-formatted output of tests.

With this patch, ctags is run in a subshell; and the subshell the
stderr and stdout are redirected to SHSTDERR.tmp and SHSTDOUT.tmp.  As
the result the crash report doesn't disturbs the well-formatted output
of tests but can be refereed as a separated file later if needed.

Issue reporeted by @vhda in #60.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
units: remove old test.units target

The old implementation is complicated after incremental extending.
Now test.units target is just an alias for units target.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
units: fix a bug in reporting the number of passed results

In old code, the number is returned from a function(count_list).
However, it seems that a function cannot return larger number.
So this patch lets count_list print the number directly instead
of returning it.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
units: simplify the definition of clean-units target

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
units: Allow selection of units of multiple languages

Suggested by @vhda in #118.
member_p helper function is used.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
units: Allow selection of units of multiple languages