C++: Fix resource-not-released-in-destructor CP

By moving a disjunct outside the scope of an `exists(Function f`
variable it doens't use, the code becomes clearer and can be optimized
better.

The CP in the QL code did not lead to a CP at evaluation time since the
optimizer was smart enough to compensate for it:

    376161  ~37597630%     {0} r1 = SCAN functions OUTPUT {}
    1       ~0%            {0} r2 = STREAM DEDUP r1

Before this change, the largest tuple count in `leakedInSameMethod` on
bitcoin/bitcoin was 2M. Now it's 400k.

cpp/ql/src/jsf/4.10 Classes/AV Rule 79.ql

@@ -230,13 +230,13 @@ predicate leakedInSameMethod(Resource r, Expr acquire) {
         )
       )
     )
-    or
-    exists(FunctionAccess fa, string kind |
-      // the address of a function that releases `r` is taken (and likely
-      // used to release `r` at some point).
-      r.acquisitionWithRequiredKind(acquire, kind) and
-      fa.getTarget() = r.getAReleaseExpr(kind).getEnclosingFunction()
-    )
+  )
+  or
+  exists(FunctionAccess fa, string kind |
+    // the address of a function that releases `r` is taken (and likely
+    // used to release `r` at some point).
+    r.acquisitionWithRequiredKind(acquire, kind) and
+    fa.getTarget() = r.getAReleaseExpr(kind).getEnclosingFunction()
   )
 }