Investigate logical expression type rules

[dcodeIO]

While working on #1129 I noticed that the rules in place for logical && and || are weird.

if (someObject && someInt) // cannot convert RHS integer to LHS object
if (someObject && someBool) // cannot convert RHS boolean to LHS object
var foo = aFooNullable || bFoo; // cannot convert RHS non-nullable to LHS nullable

Boolean context is especially strange. Pinning here so we don't forget.