Allow asan, msan and ubsan to be configured with shared libraries

The background story is that util/shlib_wrap.sh was setting LD_PRELOAD
or similar platform dependent variables, just in case the shared
libraries were built with -rpath.  Unfortunately, this doesn't work
too well with asan, msan or ubsan.

So, the solution is to forbid the combination of shared libraries,
-rpath and any of the sanity analyzers we can configure.

This changes util/shlib_wrap.sh so it only contains the code that sets
LD_PRELOAD when -rpath has been used when configuring.

Reviewed-by: Rich Salz <rsalz@openssl.org>