Fix test wrt. deprecation of float to int conversions

Instead of passing `1073746742.75` to an int parameter, we just do the
calculation upfront (and round up), since the actual calculation does
not matter here anyway.

ext/sysvshm/tests/bug72858.phpt

@@ -12,7 +12,7 @@ if (substr(PHP_OS, 0, 3) != "WIN") { print "skip windows only"; }
 <?php
 
 $v1=100;
-$v2=0xffffffff / 4 + 0x1337;
+$v2=0x4fffffff + 0x1337;
 shm_attach($v1,$v2);
 
 ?>