Revert "Optimizing: Tag basic block allocations with their source."

Reverting so that we can have more discussion about the STL API.

This reverts commit 91e11c0c840193c6822e66846020b6647de243d5.

Change-Id: I187fe52f2c16b6e7c5c9d49c42921eb6c7063dba
diff --git a/compiler/optimizing/code_generator.cc b/compiler/optimizing/code_generator.cc
index bb780dc..3f69270 100644
--- a/compiler/optimizing/code_generator.cc
+++ b/compiler/optimizing/code_generator.cc
@@ -171,7 +171,7 @@
 
 HBasicBlock* CodeGenerator::FirstNonEmptyBlock(HBasicBlock* block) const {
   while (block->IsSingleJump()) {
-    block = block->GetSuccessor(0);
+    block = block->GetSuccessors().Get(0);
   }
   return block;
 }