add implementation of UNREACHABLE for MSVC in release mode. This reduces code size of Z3 by 0.1%  \o/
add implementation of UNREACHABLE for MSVC in release mode.
This reduces code size of Z3 by 0.1%  \o/

Signed-off-by: Nuno Lopes <c61bc7502a9d053e92b2bfd97b87138a818cfe20@microsoft.com>

375670450/z3,syjzwjj/z3,traiansf/z3-java,gmeer/z3,syjzwjj/z3,huangshiyou/z3,wujunzero/z3,Baha/z3,kyledewey/z3,mschlaipfer/z3,seahorn/z3,melted/z3,jirislaby/z3,conceptofproof/z3,zhuyue1314/z3,kyledewey/z3,zardus/z3,traiansf/z3-java,jirislaby/z3,huangshiyou/z3,375670450/z3,zhuyue1314/z3,felixdae/z3,belyaev-mikhail/z3,jirislaby/z3,hguenther/z3,mschlaipfer/z3,felixdae/z3,Baha/z3,conceptofproof/z3,kyledewey/z3,traiansf/z3-java,wujunzero/z3,seahorn/z3,375670450/z3,gmeer/z3,belyaev-mikhail/z3,gmeer/z3,jirislaby/z3,belyaev-mikhail/z3,melted/z3,seahorn/z3,hguenther/z3,kyledewey/z3,jirislaby/z3,zardus/z3,mschlaipfer/z3,Baha/z3,375670450/z3,syjzwjj/z3,Baha/z3,felixdae/z3,zardus/z3,zardus/z3,hguenther/z3,felixdae/z3,gmeer/z3,gmeer/z3,melted/z3,kyledewey/z3,traiansf/z3-java,conceptofproof/z3,melted/z3,wujunzero/z3,zhuyue1314/z3,syjzwjj/z3,conceptofproof/z3,zhuyue1314/z3,conceptofproof/z3,mschlaipfer/z3,huangshiyou/z3,375670450/z3,wujunzero/z3,huangshiyou/z3,hguenther/z3,seahorn/z3,conceptofproof/z3,kyledewey/z3,zhuyue1314/z3,jirislaby/z3,belyaev-mikhail/z3,375670450/z3,felixdae/z3,gmeer/z3,wujunzero/z3,felixdae/z3,belyaev-mikhail/z3,syjzwjj/z3,traiansf/z3-java,seahorn/z3,mschlaipfer/z3,wujunzero/z3,hguenther/z3,melted/z3,huangshiyou/z3,melted/z3,zardus/z3,huangshiyou/z3,Baha/z3,traiansf/z3-java,Baha/z3,belyaev-mikhail/z3,seahorn/z3,syjzwjj/z3,hguenther/z3,zardus/z3,zhuyue1314/z3,mschlaipfer/z3