[gdb/testsuite] Require debug info for gdb.tui/tui-layout-asm-short-prog.exp

[gdb/testsuite] Require debug info for gdb.tui/tui-layout-asm-short-prog.exp

When running test-case gdb.tui/tui-layout-asm-short-prog.exp on SLE-12-SP3
aarch64, I run into:
...
FAIL: gdb.tui/tui-layout-asm-short-prog.exp: check asm box contents
FAIL: gdb.tui/tui-layout-asm-short-prog.exp: check asm box contents again
...
due to:
...
(gdb) file tui-layout-asm-short-prog^M
Reading symbols from tui-layout-asm-short-prog...^M
(No debugging symbols found in tui-layout-asm-short-prog)^M
...

I managed to reproduce the same behaviour on openSUSE Leap 15.4 x86_64, by
removing the debug option.

Fix this by making the test-case unsupported if no debug info is found.

Tested on x86_64-linux.