Fix massive resource leaks in the bytecode reader. Reading a bytecode file

Fix massive resource leaks in the bytecode reader.  Reading a bytecode file
with ParseBytecodeFile used to leak both a ModuleProvider (and related
bytecode parser stuff attached to it) AND a file descriptor, which was
never closed.  This prevented gccld/llvm-ld/llvm-link from linking together
apps with more that ~252 .bc files on darwin.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30912 91177308-0d34-0410-b5e6-96231b3b80d8