Removes ApacheMapTest and fixes IdentityHashMapTest

- ApacheMapTest is not testing anything different than HashMapTest. It looks
like it existed because HashMapTest wasn't extending TestMap before.

- Removes the override to disable testing of null value in IdentityHashMapTest.
I don't know why they commented JRE version didn't handle null values properly.

Change-Id: I3cded9da62d10e10e05088f5eb83347e51276f62
Introduces a system property to debug js in HtmlUnit

To open the javascript debugging window for htmlunit,
-Dgwt.htmlunit.debug could be passed while running a
GWTTestCase.

Change-Id: Ic6a51ba2927f81bd35f37906bea6b09fdbcbdd16
Removes copies of junit.html in I18N

Change-Id: If2efa1cd6947b8d89b0d49c1acb6e6b40f7035cd
Super Dev Mode: skip the compile if no files have changed

(Assumes that the binding properties, module files, and resource
files are the only inputs that matter.)

Change-Id: I573af2db28389184cd8658710e0cc8a9ff7f5799
Review-Link: https://gwt-review.googlesource.com/#/c/8640/
Modify cldr-import to work with last cldr-25 version

- cldr-25 needs some code modifications, and java 7 to compile.
- Updated instructions.

Change-Id: I56d61621591138ac2b568ebe8bb2b7d5173bb3d2
Update i18n stuff produced with cldr-import (v25)

- This is all the stuff produced by the GenerateGwtCldr script
  against CLDR v25 after applying Google's customized patch
  GWT_TOOLS/lib/cldr/25/GoogleMods.patch
- Modified tests so as they match new changes in v25
- Added locale data produced by internal Google python scripts.

Change-Id: I5d02c0587ed16dfedcfa64ad00a033808110d84b
adding i18n only task

Change-Id: Iba97383ce84c38935cf98e4c2222272429e57a5e