[CFI] Fix Direct Call Issues in CFI Dispatch Table (#69663)

I discovered two issues for when a CFI dispatch table entry is used as a
direct call.
# Inlining
There is the possibility that the dispatch table entry contains only a
single function pointer:
```
; Function Attrs: naked nocf_check
define private void @.cfi.jumptable() #6 align 8 { entry:
  call void asm sideeffect "jmp ${0:c}@plt\0Aint3\0Aint3\0Aint3\0A", "s"(ptr @_Z7throw_ei)
  unreachable
}
```
If this function is inlined, the unreachable follows and ruins the
containing function.
# Exception Handling
The dispatch table is always marked NoUnwind. This is fine if the
entries are never used directly, but if a direct call is used which the
containing function expects to throw, it will no longer throw and the
exception handling code will be lost.