Skip gdb.dap/pause.exp on Solaris [PR34548]

As detailed in PR PR dap/34548, the gdb.dap/pause.exp test runs
indefinitely on Solaris.  To allow make check to finish, it needs to be
terminated manually.

To avoid this, this patch skips the test.

Tested on x86_64-pc-solaris2.11, sparcv9-sun-solaris2.11, and
x86_64-pc-linux-gnu.

Approved-By: Tom Tromey <tom@tromey.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=34548