[DWARF v5] Reposting r337981, which was reverted in r337997 due to a test...

[DWARF v5] Reposting r337981, which was reverted in r337997 due to a test failure in debuginfo_tests.
The test failure was caused by the compiler not emitting a __debug_ranges section with DWARF 4 and
earlier when no ranges are needed. The test checks for the existence regardless.

llvm-svn: 338081