[gdb/testsuite] Fix funcall_ref.exp xpass

[gdb/testsuite] Fix funcall_ref.exp xpass

When running gdb.ada/funcall_ref.exp I run into two XPASSes:
...
(gdb) p get ("Hello world!")^M
$1 = (n => 12, s => "Hello world!")^M
(gdb) XPASS: gdb.ada/funcall_ref.exp: p get ("Hello world!")
ptype get ("Hello world!")^M
type = <ref> record^M
    n: natural;^M
    s: access array (1 .. n) of character;^M
end record^M
(gdb) XPASS: gdb.ada/funcall_ref.exp: ptype get ("Hello world!")
...

The xfails are documented in funcall_ref.exp:
...
 # Currently, GCC describes such functions as returning pointers (instead of
 # references).
 setup_xfail *-*-*
...

Using gnatmake 4.8, we can reproduce the XFAILs:
...
(gdb) p get ("Hello world!")^M
$1 = (access foo.bar) 0x6147b0 <system.secondary_stack.chunk+48>^M
(gdb) XFAIL: gdb.ada/funcall_ref.exp: p get ("Hello world!")
ptype get ("Hello world!")^M
type = access record^M
    n: natural;^M
    s: access array (1 .. n) of character;^M
end record^M
(gdb) XFAIL: gdb.ada/funcall_ref.exp: ptype get ("Hello world!")
...

Fix the XPASSes by:
- removing the xfail setup
- switching the order of the two tests
- detecting the "access record" type and declaring the first test unsupported,
  and skipping the second test

Tested on x86_64-linux, both with gnatmake 4.8.5 and gnatmake 7.5.0.

gdb/testsuite/ChangeLog:

2020-02-19  Tom de Vries  <tdevries@suse.de>

	* gdb.ada/funcall_ref.exp: Replace xfail setup by unsupported check.