KOBAYASHI Shuji f92867a59e Refine the assertion failure message in mrdb print tests ...

#### Before this patch:

  ```console
  Fail: mruby-bin-debugger(print) error (mrbgems: mruby-bin-debugger)
   - Assertion[2]
      Expected true to be false.
  ```

#### After this patch:

  ```console
  Fail: mruby-bin-debugger(print) error (mrbgems: mruby-bin-debugger)
   - Assertion[2]
      Expected "$2 = undefined method 'bar' (NoMethodError)\n" to be start_with? "$2 = (eval):2: undefined method".
  ```

2019-12-24 23:20:20 +09:00

..

mrdb.rb

Removed trailing spaces

2016-09-28 12:29:41 +09:00

print.rb

Refine the assertion failure message in mrdb print tests

2019-12-24 23:20:20 +09:00