Make sure that module scope variables of extern types are default ini…

…talized (#26417)

Fixes an issue where module scope variables of an extern type where not
default initialized properly. This was caused by a dead store of
`PRIM_ZERO_VARIABLE` to a temporary, created by `makeHeapAllocations` in
the `parallel` pass.

The fix is to just set the temporary back to the "pointer"

This PR also adds a NUMLOCALES file to some C extern tests to ensure
they are run in nightly gasnet+asan tests

Resolves #26406

Testing
- [x] ran `start_test` with GASNet + ASAN tesing on
`test/extern/bharshbarg/` and `test/extern/ferguson/`
- [x] full paratest without comm
- [x] full paratest with comm

[Reviewed by @mppf]

compiler/passes/parallel.cpp

@@ -1145,6 +1145,12 @@ makeHeapAllocations() {
           call->getStmtExpr()->insertBefore(new DefExpr(tmp));
           call->getStmtExpr()->insertBefore(new CallExpr(PRIM_MOVE, tmp, new CallExpr(PRIM_GET_MEMBER_VALUE, use->symbol(), heapType->getField(1))));
           use->replace(new SymExpr(tmp));
+          if (call->isPrimitive(PRIM_ZERO_VARIABLE)) {
+            // aftering zeroing the value, we need to set it back
+            // otherwise its a dead store
+            call->getStmtExpr()->insertAfter(
+              new CallExpr(PRIM_SET_MEMBER, use->symbol(), heapType->getField(1), tmp));
+          }
         }
       } else if (use->parentExpr)
         INT_FATAL(var, "unexpected case");

test/extern/ferguson/NUMLOCALES

@@ -0,0 +1 @@
+2