Add tests to make sure ChromeELF.dll imports are correct:

1. Make sure chrome_elf.dll imports nothing besides kernel32 and some
msvc libs (DEBUG builds)
2. make sure chrome_elf.dll is always the first entry in chrome.exe's
import table.

Review URL: https://codereview.chromium.org/109483003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242834 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242834