LTO: Fixes for renaming issues with offload/OpenMP [PR104285]

LTO: Fixes for renaming issues with offload/OpenMP [PR104285]

gcc/lto/ChangeLog:

	PR middle-end/104285
	* lto-partition.cc (maybe_rewrite_identifier): Use get_identifier
	for the returned string to be usable as hash key.
	(validize_symbol_for_target): Hence, use return value directly.
	(privatize_symbol_name_1): Track maybe_rewrite_identifier renames.
	* lto.cc (offload_handle_link_vars): Move function up before ...
	(do_whole_program_analysis): Call it after static renamings.
	(lto_main): Move call after static renamings.

libgomp/ChangeLog:

	PR middle-end/104285
	* testsuite/libgomp.c++/target-same-name-2-a.C: New test.
	* testsuite/libgomp.c++/target-same-name-2-b.C: New test.
	* testsuite/libgomp.c++/target-same-name-2.C: New test.
	* testsuite/libgomp.c-c++-common/target-same-name-1-a.c: New test.
	* testsuite/libgomp.c-c++-common/target-same-name-1-b.c: New test.
	* testsuite/libgomp.c-c++-common/target-same-name-1.c: New test.