Merge pull request #19578 from ronawho/fix-ofi-fenced-am-cp

Fix an MCM issue between AMs and PUTs in ofi msg-order-fence (cherry-pick #19575)

Fix a race where an AM wasn't waiting for outstanding PUTs to complete
for ofi message-order-fence. For a case like:

```chpl
var a = 0;
on Locales[numLocales-1] {
  a = 1;
  on Locales[0] {
    assert(a == 1);
  }
}
```

the AM (`on Locales[0]`) wasn't waiting for the pending PUT (`a = 1`) to
complete. The comments in the code indicate we thought we were handling
this correctly by issuing our AM with `FI_FENCE` to wait for any pending
operations, but that does not appear to be happening.

Here I'm applying a hotfix to extend how we force message visibility to
stop skipping the target node. We want to understand what's going on
here better, but for now I just want to get a base fix in to address
failures we're seeing.

Also add a CHANGES.md entry since we're tying to land this hotfix in the
1.26 release.

CHANGES.md

@@ -1,6 +1,14 @@
 Release Changes List
 ====================
 
+version 1.26.0.1
+================
+
+This version is a slight variation on the 1.26.0 release containing a
+late-breaking bug fix that is specific to CHPL_COMM='ofi' when using the
+'cxi' provider.
+
+
 version 1.26.0
 ==============
 

runtime/src/comm/ofi/comm-ofi.c

@@ -4288,8 +4288,7 @@ void amReqFn_msgOrdFence(c_nodeid_t node,
   // to any node are visible.  Similarly, for GETs we have to ensure
   // that previous AMOs and PUTs to the target node are visible, and for
   // PUTs we have to ensure that previous AMOs to the target node are
-  // visible.  Do that here for all nodes except this op's target.  For
-  // that node, we'll use a fenced send instead.
+  // visible.  Do that here for all nodes.
   //
   chpl_bool havePutsOut = false;
   chpl_bool haveAmosOut = false;
@@ -4298,7 +4297,7 @@ void amReqFn_msgOrdFence(c_nodeid_t node,
   case am_opExecOn:
   case am_opExecOnLrg:
     forceMemFxVisAllNodes(true /*checkPuts*/, true /*checkAmos*/,
-                          node /*skipNode*/, tcip);
+                          -1 /*skipNode*/, tcip);
     havePutsOut = (tcip->putVisBitmap != NULL
                    && bitmapTest(tcip->putVisBitmap, node));
     haveAmosOut = (tcip->amoVisBitmap != NULL
@@ -4308,7 +4307,7 @@ void amReqFn_msgOrdFence(c_nodeid_t node,
     {
       chpl_bool amoHasMemFx = (req->amo.ofiOp != FI_ATOMIC_READ);
       forceMemFxVisAllNodes(amoHasMemFx /*checkPuts*/, true /*checkAmos*/,
-                            node /*skipNode*/, tcip);
+                            -1 /*skipNode*/, tcip);
       havePutsOut = (amoHasMemFx
                      && tcip->putVisBitmap != NULL
                      && bitmapTest(tcip->putVisBitmap, node));