[analyzer] When performing a binary operation on symbolic operands, we convert the...

[analyzer] When performing a binary operation on symbolic operands, we convert the symbol values to a common type. But in a relational operation, the result is an 'int' or 'bool', which may not be the appropriate type to convert the operands to. In these cases, use the left-hand operand's type as the conversion type.

There's no associated test for this because fully-constrained symbolic values are evaluated ahead of time in normal expressions. This can only come up in checker-constructed expressions (like the ones in an upcoming patch to CStringChecker).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@133041 91177308-0d34-0410-b5e6-96231b3b80d8