MSVS names '.map' file using only module's name, so both 'a.exe' and 'a.dll' will have 'a.map' file. To distinguish an originating module, we're now checking for image base which is always 00400000 for .exe files, and not 00400000 for .dlls.

Verified that windows-tick-processor can now process logs from Chromium using .map file generated for 'chrome.dll', an that it still works for V8's 'shell.exe'.

Review URL: http://codereview.chromium.org/172044

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2699 ce2b1a6d-e550-0410-aec6-3dcde31c8c00