The Remarks Streamer's installation seemed a bit overly complex, so simplify it in a few places:
* Refactor sil-opt to install the remarks options into the SILOptions for the SILModule
This reduces the parameter bloat in createSILRemarkStreamer. All of this data is freely derivable from the SILModule alone.
* Refactor createSILRemarkStreamer into SILRemarkStreamer::create
With the new reduction in parameters, we can hide the internal constructor and introduce a smart constructor that vends a unique pointer to clients.
* setSILRemarkStreamer -> installSILRemarkStreamer
Since the information to create a streamer is now entirely derivable from a module, remove a layer of abstraction and have the module directly construct a streamer for itself.
* Give SILRemarkStreamer its own LLVMContext
The remarks streamer just needs scratch space. It's not actually "installed" in a given context. There no reason to use Swift's Global Context here.
* Give the SILRemarkStreamer ownership of the underlying file stream
The SILModule didn't actually use this member, and it seems like somebody needs to own it, so just give it to the remarks streamer directly.
Specifically, I split it into 3 initial categories: IR, Utils, Verifier. I just
did this quickly, we can always split it more later if we want.
I followed the model that we use in SILOptimizer: ./lib/SIL/CMakeLists.txt vends
a macro (sil_register_sources) to the sub-folders that register the sources of
the subdirectory with a global state variable that ./lib/SIL/CMakeLists.txt
defines. Then after including those subdirs, the parent cmake declares the SIL
library. So the output is the same, but we have the flexibility of having
subdirectories to categorize source files.
