When using a precompiled preamble with detailed preprocessing records,

trap the serialized preprocessing records (macro definitions, macro
instantiations, macro definitions) from the generation of the
precompiled preamble, then replay those when walking the list of
preprocessed entities. This eliminates a bug where clang_getCursor()
wasn't able to find preprocessed-entity cursors in the preamble.

llvm-svn: 120396