...with latest Clang trunk towards Clang 9.  All the no-longer necessary hacks
are made conditional on new NEED_CLANG_LINUX_UBSAN_RTTI_VISIBILITY, which is
still set for UBSan builds with older Clang on Linux (but which should
eventually be purged).

Various classes needed additional SAL_DLLPUBLIC_RTTI annotations, as building
with UBSan instrumentation can generate references to RTTI symbols from
additional places like outside a dynamic library that used to hide those symbols
by default (but used to not hide them for old UBSan builds thanks to the
-fvisibility-ms-compat hack).

The odr-violation suppressions in solenv/sanitizers/asan-suppressions (which is
not referenced from anywhere in the code base, but meant to be included in an
ASan/UBSan build's ASAN_OPTIONS env var) are also no longer needed when
NEED_CLANG_LINUX_UBSAN_RTTI_VISIBILITY is false.

Change-Id: I24ec3e388b0cbab50dbe2bf008d9569bff7bf25a
Reviewed-on: https://gerrit.libreoffice.org/70829
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>