Fix build failure on Windows with older binutils

Fix build failure on Windows with older binutils

This is the build failure on Windows with binutils for which GNU as accepts
the --gdwarf-5 switch but GNU ld generates broken binaries with DWARF 5.

We already have the HAVE_LD_BROKEN_PE_DWARF5 kludge to disable DWARF 5 in
this case but it only tames the DWARF version in the compiler, so the
driver still passes --gdwarf-5 when invoked on an assembly file with -g.

gcc/
	PR target/101377
	* gcc.c (ASM_DEBUG_DWARF_OPTION): Set again to --gdwarf2 in
	the case where HAVE_AS_WORKING_DWARF_N_FLAG is not defined
	and HAVE_LD_BROKEN_PE_DWARF5 is defined.