Fix:
- Adding setWidget(browser) to setUp(), so that browser occupies the
whole shell instead of half of it.

Refactor:
- Consolidated most browser tests into a single class. (There were many
classes with only a single test case).

Speeding up some test cases:
- test_forward : There is no need to wait in this test case as no pages
are loded.
- test_back : as above.
- test_isBackEnabled : as above.
- test_refresh : as above.
- test_stop : There is no need to sleep for 10 seconds after stop
finishes. Stop is not async.

- Split test_setTextLjava_lang_String into that and "test_setTextNull"

etc... similar logic for most refactored tests.

Change-Id: I31b79feeabcc28685b56e0ce1315fd4065f8e206
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=499387
Signed-off-by: Leo Ufimtsev <lufimtse@redhat.com>