Fix a couple issues with the JIT and multiple modules:

1. The "JITState" object creates a PassManager with the ModuleProvider that the
   jit is created with.  If the ModuleProvider is removed and deleted, the
   PassManager is invalid.

2. The Global maps in the JIT were not invalidated with a ModuleProvider was 
   removed.  This could lead to a case where the Module would be freed, and a 
   new Module with Globals at the same addresses could return invalid results.

llvm-svn: 51384