[asan] Patch - fix an ICE in asan.c

[Markus Trippelsdorf]

Another ICE:

 % cat test.ii
 int i;

 % g++ -faddress-sanitizer -c -g -O1 test.ii
test.ii:1:7: internal compiler error: Segmentation fault
  int i;
       ^
0xa5cb5f crash_signal
        /home/markus/gcc/gcc/toplev.c:334
inconsistent DWARF line number info
0x4cf588 cp_classify_record
        /home/markus/gcc/gcc/cp/cp-lang.c:131
0x7ee7e3 record_type_tag
        /home/markus/gcc/gcc/dwarf2out.c:16914
0x7ee7e3 gen_struct_or_union_type_die
        /home/markus/gcc/gcc/dwarf2out.c:19078
0x7ee7e3 gen_tagged_type_die
        /home/markus/gcc/gcc/dwarf2out.c:19303
0x7ee7e3 gen_tagged_type_die
        /home/markus/gcc/gcc/dwarf2out.c:19246
0x7f5dce gen_type_die_with_usage
        /home/markus/gcc/gcc/dwarf2out.c:19450
0x7f6b9c modified_type_die
        /home/markus/gcc/gcc/dwarf2out.c:10180
0x7f68c5 modified_type_die
        /home/markus/gcc/gcc/dwarf2out.c:10238
0x7f8cd0 add_type_attribute
        /home/markus/gcc/gcc/dwarf2out.c:16486
0x7f4bf1 gen_formal_parameter_die
        /home/markus/gcc/gcc/dwarf2out.c:17079
0x7f520b gen_formal_types_die
        /home/markus/gcc/gcc/dwarf2out.c:17175
0x7f181c gen_subprogram_die
        /home/markus/gcc/gcc/dwarf2out.c:17909
0x7f8075 force_decl_die
        /home/markus/gcc/gcc/dwarf2out.c:19733
0x7f8721 resolve_addr
        /home/markus/gcc/gcc/dwarf2out.c:22661
0x7f83f9 resolve_addr
        /home/markus/gcc/gcc/dwarf2out.c:22683
0x7f83f9 resolve_addr
        /home/markus/gcc/gcc/dwarf2out.c:22683
0x807392 dwarf2out_finish
        /home/markus/gcc/gcc/dwarf2out.c:23305
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
-- 
Markus