ASan global-overflow.cpp etc. FAIL on SPARC

[rorth]

When enabling ASan on SPARC with PR #107405, two tests FAIL in similar ways:

  AddressSanitizer-sparc-sunos :: TestCases/global-overflow.cpp
  AddressSanitizer-sparc-sunos :: TestCases/large_func_test.cpp
  AddressSanitizer-sparc-sunos-dynamic :: TestCases/global-overflow.cpp
  AddressSanitizer-sparc-sunos-dynamic :: TestCases/large_func_test.cpp

For both tests, at -O1 and above one line number in the stacktrace is missing:

    #0 0x00100f1c in main compiler-rt/test/asan/TestCases/global-overflow.cpp

It turns out this happens because .debug_line, which llvm-symbolizer uses to map the address to source file and line, is wrong, as seen with llvm-dwarfdump --debug-line:

0x0000000000100f1c      0      0      0   0             0       0 

while at -O0 things are fine:

    #0 0x00100ed8 in main compiler-rt/test/asan/TestCases/global-overflow.cpp:14:13

0x0000000000100ed8     14     13      0   0             0       0  is_stmt

g++ gets this right OTOH: the test works irrespective of optimization.