* gdb.trace/collection.exp (executable): New.
(binfile): Use it.
(fpreg, spreg, pcreg): New.
(test_register): Use gdb_test_multiple. Pass /x to print.
(prepare_for_trace_test): New.
(run_trace_experiment): Use "continue", not gdb_run_cmd.
(gdb_collect_args_test, gdb_collect_argstruct_test)
(gdb_collect_argarray_test, gdb_collect_locals_test): Use
prepare_for_trace_test.
(gdb_collect_registers_test): Use prepare_for_trace_test. Use
fpreg, spreg and pcreg.
(gdb_collect_expression_test, gdb_collect_globals_test): Use
prepare_for_trace_test.
(gdb_trace_collection_test): Use fpreg, spreg and pcreg. Don't
try to detect tracing support here. Don't set breakpoints at
`begin' or `end' here.
<global scope>: Use clean_restart. Run to main before checking
for tracing support. Check for for tracing support here.