Recommit r270547 ([llvm-dwarfdump] - Teach dwarfdump to decompress debug sections in zlib style.)

Fix was:
1) Had to regenerate dwarfdump-test-zlib.elf-x86-64, dwarfdump-test-zlib-gnu.elf-x86-64
(because llvm-symbolizer-zlib.test uses that inputs for its purposes and failed).
2) Updated llvm-symbolizer-zlib.test (updated used call function address to match new files + 
added one more check for newly created dwarfdump-test-zlib-gnu.elf-x86-64 binary input).
3) Updated comment in dwarfdump-test-zlib.cc.

Original commit message:
[llvm-dwarfdump] - Teach dwarfdump to decompress debug sections in zlib style.

Before this llvm-dwarfdump only recognized zlib-gnu compression style of headers,
this patch adds support for zlib style. 
It looks reasonable to support both styles for dumping,
even if we are not going to suport generating of deprecated gnu one.

Differential revision: http://reviews.llvm.org/D20470

llvm-svn: 270557