C++: Fix the following join (I canceled it mid-way):

```
Tuple counts for SsaInternals#7b362d2f::getAPriorDefinition#1#ff/2@bfabfc7o after 11.4s:
  1000      ~4%     {2} r1 = SCAN Ssa#da392372::Make#SsaInternals#7b362d2f::SsaInput#::Definition::definesAt#3#dispred#ffff OUTPUT In.1, In.0
  474321529 ~0%     {4} r2 = JOIN r1 WITH SsaInternals#7b362d2f::DefOrUse::hasIndexInBlock#3#dispred#ffff_3012#join_rhs ON FIRST 1 OUTPUT Lhs.1, Rhs.2, Rhs.3, Rhs.1
  0         ~0%     {2} r3 = JOIN r2 WITH SsaInternals#7b362d2f::SsaCached::lastRefRedef#4#ffff ON FIRST 3 OUTPUT Lhs.3, Rhs.3
  0         ~0%     {2} r4 = JOIN r3 WITH SsaInternals#7b362d2f::nodeToDefOrUse#3#fff_10#join_rhs ON FIRST 1 OUTPUT Lhs.1, Rhs.1 'result'
  0         ~0%     {2} r5 = JOIN r4 WITH SsaInternals#7b362d2f::ssaDefinition#1#ff_10#join_rhs ON FIRST 1 OUTPUT Rhs.1 'defOrUse', Lhs.1 'result'
                    return r5
```

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/SsaInternals.qll

@@ -676,7 +676,8 @@ private Definition ssaDefinition(Def def) {
 /** Gets a node that represents the prior definition of `node`. */
 private Node getAPriorDefinition(SsaDefOrUse defOrUse) {
   exists(IRBlock bb, int i, SourceVariable sv, Definition def, DefOrUse defOrUse0 |
-    SsaCached::lastRefRedef(def, bb, i, ssaDefinition(defOrUse)) and
+    SsaCached::lastRefRedef(pragma[only_bind_into](def), pragma[only_bind_into](bb),
+      pragma[only_bind_into](i), ssaDefinition(defOrUse)) and
     def.getSourceVariable() = sv and
     defOrUse0.hasIndexInBlock(bb, i, sv) and
     nodeToDefOrUse(result, defOrUse0, _)