[docs] Remove an example that isn't well formed LLVM IR and trips up the

[docs] Remove an example that isn't well formed LLVM IR and trips up the
Sphinx syntax highlighter.

This example also doesn't really make sense. There is no control flow or
clarification of what the `Safe:` block exists to do... If we want
examples here, we should make them much more clear in addition to making
them well formed IR sequences.

llvm-svn: 338981