gdb/testsuite: Remove duplicates from gdb.base/watchpoints.exp

When running the testsuite, I have:

    Running ../gdb/testsuite/gdb.base/watchpoints.exp ...
    DUPLICATE: gdb.base/watchpoints.exp: watchpoint hit, first time

Fix by adjusting the test names where appropriate.

Tested on x86_64-linux.
1 file changed