cygprofile: Refactor cyglog_to_orderfile.py.

No functional changes. This will make it possible to generate an orderfile
with offsets that are not produced from a profile run made by
orderfile_generator. Also creates test_utils.py as I noticed there was
a lot of reuse.

Bug: 758566
Change-Id: I22b13ecfe10a630ab4c2dcb1c67caf30e86342c5
Reviewed-on: https://chromium-review.googlesource.com/897563
Commit-Queue: Matthew Cary <mattcary@chromium.org>
Reviewed-by: Egor Pasko <pasko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#536378}

tools/cygprofile/check_orderfile.py

@@ -86,8 +86,8 @@ def main():
 
   symbol_extractor.SetArchitecture(options.arch)
   obj_dir = cygprofile_utils.GetObjDir(binary_filename)
-  symbol_to_sections_map = \
-      cyglog_to_orderfile.GetSymbolToSectionsMapFromObjectFiles(obj_dir)
+  symbol_to_sections_map = cyglog_to_orderfile.ObjectFileProcessor(
+      obj_dir).GetSymbolToSectionsMap()
   section_to_symbols_map = cygprofile_utils.InvertMapping(
       symbol_to_sections_map)
   symbols = patch_orderfile.GetSymbolsFromOrderfile(orderfile_filename,