Added option parsing to the lldb_perf_clang performance test.
[modules] When a MacroInfo object is deserialized, allocate and store its submodule ID.
[PCH/Modules] De/Serialize MacroInfos separately than MacroDirectives.

-Serialize the macro directives history into its own section
-Get rid of the macro updates section
-When de/serializing an identifier from a module, associate only one macro per
 submodule that defined+exported it.