[Embedded] Implement _swift_exceptionPersonality

[rauhul]

Description

When using C++ interoperability with Embedded Swift, we end up with a reference to the _swift_exceptionPersonality function, which is not defined in the Embedded Swift runtime. The result is a linker failure when using Embedded Swift with C++ interoperability and exceptions.

Lets just implement this in the embedded runtime to fatal error.

rdar://164423867 (Embedded Swift + C++ interoperability references undefined _swift_exceptionPersonality function)