Use the debugginess of the python interpreter when symlinking _lldb.pyd.

Previously we would pass an argument to finishSwigWrapperClasses.py which
specified whether this was a debug or a release build.  But sometimes
CMAKE_BUILD_TYPE would not be set to anything, causing this argument
to be empty when passed in.  The only purpose of this argument was to
determine whether or not to append _d to the extension module when
creating the symlink.  This is only necessary when doing a debug
build of LLDB on Windows, which implies a debug interpreter, so we
replace this with a check to see if the running interpreter is a debug
one, and append _d if so.

llvm-svn: 235559