t/run/switchI.t: Add descriptions to tests lacking them.

This entailed placing the 'grep' in a 'do' block.  Trying to add the
description without the 'do' block merely added it to the list being grepped
-- which prevented the description from being printed.

Thanks to Matt Follett and Steve Lembark at St. Louis Perl Hackathon for
diagnosis.
t/run/switchp.t: Add descriptions to all tests.

For: RT #115780
t/run/switchd.t: Add descriptions to tests lacking them.

For: RT #115784
t/op/args.t: Add descriptions for tests lacking them.

In one case, used an inline comment as test description.

For: RT #115792
t/run/script.t: Add descriptions to all tests.

Replace hard-coded tests with functions from test.pl.
Correct error in calling plan.

For: RT #115776
t/run/switchF1.t: Add descriptions to tests in t/run/switchF1.t.

For: RT #115896
t/run/switchx.t: Add descriptions to tests lacking them.

The tests which lacked descriptions are in sample files used by the test file.
Better description as suggested by Lukas Mai.

For: RT #115782
Add descriptions to tests lacking them.

Accomplished programmatically by modifying sub try().
t/win32/runenv.t: Correct syntax error reported by bulk88++.

Part of: RT #115788
Add descriptions to tests in t/op/arith.t.

For: RT #115806
Merge branch 'blead' of jkeenan@perl5.git.perl.org:/perl into blead
Stop newCONSTSUB from leaking the constant under fatal warnings
Stop duplicate lex vars from leaking under fatal warnings
svleak.t: Correct test name

I got slightly confused when I added that.  I had tested both page
overflow and closure warnings (only the latter leaked), and I got
them mixed up when I wrote the test name.
Stop format closure fatal warnings from leaking
fixed typos in sample code in sort.pm documentation
Increase $sort::VERSION to 2.02
Fix memory leak in VMS's readdir().

When we got to the end of a directory we were not freeing the
buffer we'd been using.  So refactor that section of code to have
only one return.  Bug introduced in 657054d4f860463a01c5.
Remove a spurious strlen in VMS's readdir().

After setting the null byte, we turned around and pretended we
didn't know where it was and went hunting for it. Hmm.
Better escaping of dots in tovmsspec.

When converting a filename with multiple dots to native VMS syntax,
it's necessary to escape all but the last dot with a caret ('^').
We've been doing this for some time, but have been doing it blindly
such that multiple trips through the converter resulted in a
stuttering caret problem (e.g., foo^^^.bar.pl when foo^.bar.pl was
intended).

So create a convenience macro that does the escaping and make it
only escape unescaped instances and also make it check that the
escape doesn't push us off the end of the buffer we are working
on.

Use the new macro in the three most obvious places that it's
applicable.  There may be other places that also should use it.