Add -fdump-profile-report.

Add -fdump-profile-report.

When using -fprofile-report, -fdump-profile-report can be used to
print the report to a foo.c.000i.profile-report file instead
of stderr. I see it handy for comparison purpose.

gcc/ChangeLog:

	* dumpfile.c [profile-report]: Add new profile dump.
	* dumpfile.h (enum tree_dump_index): Ad TDI_profile_report.
	* passes.c (pass_manager::dump_profile_report): Change stderr
	to dump_file.