Handle missing catchpoint support in gdb.base/break.exp [PR34535]

As detailed in PR testsuite/34535, the gdb.base/break.exp test FAILs
on Solaris:

FAIL: gdb.base/break.exp: test_no_break_on_catchpoint: continue until exit (the program exited)

warning: Error inserting catchpoint 2: Your system does not support this type of catchpoint.
warning: Error inserting catchpoint 3: Your system does not support this type of catchpoint.
warning: Error inserting catchpoint 4: Your system does not support this type of catchpoint.

This patch handles that condition.

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=34535