Fix a test

To some extent, the test was wrong here.
After space is typed in this case, we wait a small delay before updating
the suggestion strip so that we can display bigram predictions without
introducing delays. The suggestion strip is not displayed until then.

The test was bypassing this by simulating a press on the suggestion
strip, but for LatinIME it was not displayed yet, hence the bug.
The new code waits for the delay, makes sure the suggestion strip is
actually displaying punctuation marks, then press the mark and do
the intended test on space.

Change-Id: I18f82da1bc0a8e584e9b1bac59ff48823d78ec12