reportbuilder: import from java.lang package

Change-Id: I039f7cf28dddede48627c3c624c87741ee9de0ed
Reviewed-on: https://gerrit.libreoffice.org/11956
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>