Calling reset() disposes everything the LayoutEngine knows in its
current state. While this may have prevented some obscure crash during
exit in the past (call was added 2003-03-27), it definitely leads to a
crash if the updated LayoutEngine "patch"
http://download.icu-project.org/files/icu4c/51.1/icu-51-layout-fix-10107.tgz
is applied as that sets fGlyphStorage=NULL (it doesn't delete
LEGlyphStorage though and thus may leak, but that patch is in the wild
now) and a later call to mpIcuLE->layoutChars() tries to access
fGlyphStorage->...() if mpIcuLE is reused.

For the patch mentioned see
http://site.icu-project.org/download/51#TOC-Known-Issues and
http://bugs.icu-project.org/trac/ticket/10107

Change-Id: I1b8f5c446c174d7d12b896b3ecd2a266645e8abc