* gdb.base/a2-run.exp: Use gdb_skip_stdio_test.
* gdb.base/corefile.exp: Expect the message "Program is being
debugged already" when we send the "corefile" command, since
the preceeding gdb_load may have connected gdb to a remote target.
* gdb.base/display.exp: Disable hardware watchpoints if new
board info variable "no_hardware_watchpoints" is true.
Replace single-letter commands with more readable ones.
* gdb.base/recurse.exp (recurse_tests): Disable hardware watchpoints
if new board info variable "no_hardware_watchpoints" is true.
* gdb.base/restore.exp (restore_tests): Call gdb_skip_stdio_tests
to see if stdio (printf) testing is possible.
* gdb.base/watchpoint.exp: Disable hardware watchpoints if new
board info variable "no_hardware_watchpoints" is true. Use new
proc "gdb_skip_stdio_tests" to see if printf tests are possible.
