Before:
```
[2020-09-18 14:03:57] (2587s) Tuple counts for RuntimeChecksBypass::uncheckedWrite#bbf#antijoin_rhs#1:
1270 ~8% {2} r1 = SCAN RuntimeChecksBypass::uncheckedWrite#bbf#shared AS I OUTPUT I.<1>, I.<0>
188197390 ~0% {3} r2 = JOIN r1 WITH #Callable::Callable::calls_dispred#bfPlus AS R ON FIRST 1 OUTPUT R.<1>, r1.<1>, r1.<0>
2425784042 ~1% {3} r3 = JOIN r2 WITH Expr::Expr::getEnclosingCallable_dispred#ff_10#join_rhs AS R ON FIRST 1 OUTPUT r2.<1>, R.<1>, r2.<2>
58 ~9% {2} r4 = JOIN r3 WITH project#RuntimeChecksBypass::checkedWrite#bfff AS R ON FIRST 2 OUTPUT r3.<0>, r3.<2>
return r4
```
After:
```
[2020-09-18 14:08:48] (5s) Tuple counts for RuntimeChecksBypass::uncheckedWrite#fff#antijoin_rhs:
24704473 ~2% {2} r1 = SCAN DataFlowPublic::localExprFlow#ff AS I OUTPUT I.<1>, I.<0>
23784154 ~6% {4} r2 = JOIN r1 WITH Expr::Expr::getEnclosingCallable_dispred#ff AS R ON FIRST 1 OUTPUT r1.<1>, 28, R.<0>, R.<1>
201391 ~2% {2} r3 = JOIN r2 WITH expressions AS R ON FIRST 2 OUTPUT r2.<2>, r2.<3>
23784154 ~0% {3} r4 = JOIN r1 WITH Expr::Expr::getEnclosingCallable_dispred#ff AS R ON FIRST 1 OUTPUT r1.<1>, R.<0>, R.<1>
1065242 ~20% {2} r5 = JOIN r4 WITH expr_value AS R ON FIRST 1 OUTPUT r4.<1>, r4.<2>
1266633 ~16% {2} r6 = r3 \/ r5
return r6
```
The documentation on `ExplicitInterfaceImplementations` says "Properties
imported from metadata can explicitly implement more than one property", so
the constraint appears to be invalid.
Previosly, we returned only the body belonging to "the most likely" implementation,
based on a CFG size heuristics. However, now that more callables are mapped to the
same entity, it makes more sense to treat such callables (to some extent) like
partial methods. This means, for instance, that data flow will branch out to all possible
implementations, much like we do for virtual dispatch.
`semmle.code.csharp.frameworks.system.Xml` is imported in `LibraryTypeDataFlow.qll`,
and therefore part of the default namespace. This means that the use of `DataFlow2`
inside `Xml.qll` overlaps with some queries. Bumping to `DataFlow3` resolves the issue.
