[mid-end] Fix declared type of personality functions

[mid-end] Fix declared type of personality functions

`build_personality_function` generates a declaration for a personality
function.  The type it declares for these functions doesn't match the
type of the actual personality functions that are defined by the C++
unwinding ABI.

This doesn't cause any crashes since the compiler never generates a call
to these decl's, and hence the type of the function is never used.
Nonetheless, for the sake of consistency and readability we update the
type of this declaration.

gcc/ChangeLog:

2019-11-05  Matthew Malcomson  <matthew.malcomson@arm.com>

	* expr.c (build_personality_function): Fix generated type to
	match actual personality functions.

From-SVN: r277846