perl: Remove unused module constructor

In the perl language module we create a new perl *module* on the fly
comprised of some preamble, the specified perl script and some
post-amble.

In the preamble we create a constructor called new(), however this can
clash with other constructors also called new.

While this can be worked around by instead of doing

  ... new CLASS

rather do

  ... CLASS->new()

While this constructor was added in commit 3b2c1d0 ("Perl: added
implementation delayed response and streaming body."), I don't see that
we actually use it anywhere (nor is it seemingly something we document)
and if we simply remove it then things still seem to work, including the
Perl pytests

  ...
  test/test_perl_application.py::test_perl_streaming_body_multiple_responses[5.38.2] PASSED
  ...
  test/test_perl_application.py::test_perl_delayed_response[5.38.2] PASSED
  test/test_perl_application.py::test_perl_streaming_body[5.38.2] PASSED
  ...

Closes: #1456
Signed-off-by: Andrew Clayton <[email protected]>

src/perl/nxt_perl_psgi.c

@@ -409,9 +409,6 @@ nxt_perl_psgi_module_create(const char *script)
 
     static const nxt_str_t  prefix = nxt_string(
         "package NGINX::Unit::Sandbox;"
-        "sub new {"
-        "   return bless {}, $_[0];"
-        "}"
         "{my $app = do \""
     );