Fix #2776: Fix instr ordering in IR Builder

* This only affected the interpreter run that relies on the
  exception-region marker instructions to determine rescue
  targets.

* The instruction ordering (old and new) doesn't affect CFG
  construction and how rescue targets are set up since the
  marker instructions are removed once the CFG is constructed.

  So, this bug only affected the default interpreter run.

core/src/main/java/org/jruby/ir/IRBuilder.java

@@ -1335,8 +1335,8 @@ private Operand protectCodeWithRescue(CodeBlock protectedCode, CodeBlock rescueB
         addInstr(new ExceptionRegionStartMarkerInstr(rescueLabel));
         Object v1 = protectedCode.run(); // YIELD: Run the protected code block
         addInstr(new CopyInstr(rv, (Operand)v1));
-        addInstr(new JumpInstr(rEndLabel));
         addInstr(new ExceptionRegionEndMarkerInstr());
+        addInstr(new JumpInstr(rEndLabel));
 
         // SSS FIXME: Create an 'Exception' operand type to eliminate the constant lookup below
         // We could preload a set of constant objects that are preloaded at boot time and use them