Introduce a -cc1 option "-emit-module", that creates a binary module

from the given source. -emit-module behaves similarly to -emit-pch,
except that Sema is somewhat more strict about the contents of
-emit-module. In the future, there are likely to be more interesting
differences.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138595 91177308-0d34-0410-b5e6-96231b3b80d8