Serialise the successor block of unconditional branches.

We'll need this for the new outlining algorithm.

Author: ptersilie

llvm/lib/YkIR/YkIRWriter.cpp

@@ -450,6 +450,8 @@ class YkIRWriter {
       //
       // opcode:
       serialiseOpcode(OpCodeBr);
+      // successor:
+      serialiseBlockLabel(I->getSuccessor(0));
     } else {
       // opcode:
       serialiseOpcode(OpCodeCondBr);