Unicode tests should be in XS::APItest, not XS::APItest::Magic.

Add a `PACKAGE =` line to reset xsubpp's idea of the current package.

This didn't actually matter, as XS::APItest "imports" all symbols from its
subpackages into the top level package, but it seems cleaner to have the
symbols in the correct package. It also makes the generated code slightly
smaller, but this doesn't really matter as it's never installed.

Remove two #if/#endif pairs related to 5.8.x/5.9.x differences, that haven't
been need for over a decade, and fix a typo in an #endif.

ext/XS-APItest/APItest.xs

@@ -1922,8 +1922,6 @@ fetch(hash, key_sv)
         OUTPUT:
         RETVAL
 
-#if defined (hv_common)
-
 SV *
 common(params)
         INPUT:
@@ -1982,8 +1980,6 @@ common(params)
         OUTPUT:
         RETVAL
 
-#endif
-
 void
 test_hv_free_ent()
         PPCODE:
@@ -2014,8 +2010,6 @@ test_share_unshare_pvn(input)
         OUTPUT:
         RETVAL
 
-#if PERL_VERSION_GE(5,9,0)
-
 bool
 refcounted_he_exists(key, level=0)
         SV *key
@@ -2041,8 +2035,6 @@ refcounted_he_fetch(key, level=0)
         OUTPUT:
         RETVAL
 
-#endif
-
 void
 test_force_keys(HV *hv)
     PREINIT:
@@ -4046,7 +4038,7 @@ CODE:
     exit(0);
 }
 
-#endif /* USE_ITHREDS */
+#endif /* USE_ITHREADS */
 
 SV*
 take_svref(SVREF sv)
@@ -4673,6 +4665,7 @@ CODE:
         (const char *)thingy, 0);
 
 
+MODULE = XS::APItest            PACKAGE = XS::APItest
 
 bool
 test_isBLANK_uni(UV ord)