[Portable Compiler] Rework return block marking.

Move the detection of blocks that contain a return from the
GBC emit pass up to Dex parsing.  This allows logic that detects
backward branches that go to method return to skip suspend checks.

Change-Id: I2a606b49850235b59c5faf237a08729e98220f4d
diff --git a/src/compiler/compiler_ir.h b/src/compiler/compiler_ir.h
index 056c308..c652f0c 100644
--- a/src/compiler/compiler_ir.h
+++ b/src/compiler/compiler_ir.h
@@ -230,8 +230,8 @@
   bool catch_entry;
   bool explicit_throw;
   bool conditional_branch;
-  bool has_return;                  // Contains a return.
-  bool dominates_return;            // Is a member of return extended basic block
+  bool terminated_by_return;        // Block ends with a Dalvik return opcode.
+  bool dominates_return;            // Is a member of return extended basic block.
   uint16_t start_offset;
   uint16_t nesting_depth;
   BBType block_type;