osl: (Win32) check allocated pipe succeeded, otherwise needs to fail

Change-Id: I0e508de4215d92700a9134e422a7b9370f387aea
Reviewed-on: https://gerrit.libreoffice.org/40300Reviewed-by: Chris Sherlock <chris.sherlock79@gmail.com>
Tested-by: Chris Sherlock <chris.sherlock79@gmail.com>

sal/osl/w32/pipe.cxx

@@ -151,6 +151,11 @@ oslPipe SAL_CALL osl_createPipe(rtl_uString *strPipeName, oslPipeOptions Options
 
     /* alloc memory */
     pPipe = osl_createPipeImpl();
+
+    assert(pPipe);  // if osl_createPipeImpl() cannot init. a new pipe, this is a failure
+    if (!pPipe)
+        return nullptr;
+
     osl_atomic_increment(&(pPipe->m_Reference));
 
     /* build system pipe name */