swift234

[SILParser] Parse basic block arguments in branch instructions

Added types when printing these args in the SIL printer.

As a side effect, I've removed the assertions that check
that we have the correct number of arguments in the Branch instruction
creation routines. The reason is that we do not have a complete block when
parsing and creating the branch instruction and it is possible to add
arguments to a basic block after creation. The assertion will be checked
by the SIL verifier.

Swift SVN r6818