Log Message:
meta-pkgs/bulk-test-icu: Update.

1. Restore qt5-qtwebkit now that it builds again -- and the build
   failure that had precipitated its temporary removal was a C++
   compatibility issue in ICU header files.

2. Make some dependencies conditional based on NOT_FOR_PLATFORM and
   ONLY_FOR_PLATFORM.  No sense in making bulk-test-icu fail on i386
   just because mongodb upstream refuses to build on i386 (unless we
   want to take on the responsibility of patching it to work).