[ConstraintSystem] Narrowly disable tryOptimizeGenericDisjunction when some of the arguments are number literals

Don't attempt this optimization if call has number literals.
This is intended to narrowly fix situations like:

```swift
func test<T: FloatingPoint>(_: T) { ... }
func test<T: Numeric>(_: T) { ... }

test(42)
```

The call should use `<T: Numeric>` overload even though the
`<T: FloatingPoint>` is a more specialized version because
selecting `<T: Numeric>` doesn't introduce non-default literal
types.

include/swift/Sema/ConstraintSystem.h

@@ -497,6 +497,10 @@ public:
   /// literal (represented by `ArrayExpr` and `DictionaryExpr` in AST).
   bool isCollectionLiteralType() const;
 
+  /// Determine whether this type variable represents a literal such
+  /// as an integer value, a floating-point value with and without a sign.
+  bool isNumberLiteralType() const;
+
   /// Determine whether this type variable represents a result type of a
   /// function call.
   bool isFunctionResult() const;