Just save XMM0-XMM15 on x64.

Not really sure why but seems like VS2010 expects XMM4 to be preserved.

Fixes headless on x64.
Skip trailing newlines in test comparison.
Move the actual test run to its own function.
Support running multiple tests in a row.
List failed tests in autocompare.
Support the verbose test compare parameter.
Merge pull request #3811 from unknownbrackets/headless

Just save XMM0-XMM15 on x64 + more headless