Enable CrossGen tests

parent #276 

Verified with "build.cmd verify" and crossgen generated all dlls successfully (although I got a bunch of warnings during generation).
Just tried but it didn't work.
We can quote all quoted arguments with an extra pair of double quotes to resolve the problem. Please check my latest commit. It executes
```
cmd /C ""path/to/k" crossgen --in "path/to/target""
```
cmd.exe gets the correct arguments after it strips the leading quote and removes trailing quote.