[Remarks] Add a specialized RemarkStreamer for SIL remarks

This allows the usage of the whole remark infrastructure developed in
LLVM, which includes a new binary format, metadata in object files, etc.

This gets rid of the YAMLTraits-based remark serialization and does the
plumbing for hooking to LLVM's main remark streamer.

For more about the idea behind LLVM's main remark streamer, see the
docs/Remarks.rst changes in https://reviews.llvm.org/D73676.

The flags are now:

* -save-optimization-record: enable remarks, defaults to YAML
* -save-optimization-record=<format>: enable remarks, use <format> for
serialization
* -save-optimization-record-passes <regex>: only serialize passes that
match <regex>.

The YAMLTraits in swift had a different `flow` setting for the debug
location, resulting in some test changes.

lib/Frontend/CompilerInvocation.cpp

@@ -999,6 +999,20 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
   Opts.EnableDynamicReplacementCanCallPreviousImplementation = !Args.hasArg(
       OPT_disable_previous_implementation_calls_in_dynamic_replacements);
 
+  if (const Arg *A = Args.getLastArg(OPT_save_optimization_record_EQ)) {
+    llvm::Expected<llvm::remarks::Format> formatOrErr =
+        llvm::remarks::parseFormat(A->getValue());
+    if (llvm::Error err = formatOrErr.takeError()) {
+      Diags.diagnose(SourceLoc(), diag::error_creating_remark_serializer,
+                     toString(std::move(err)));
+      return true;
+    }
+    Opts.OptRecordFormat = *formatOrErr;
+  }
+
+  if (const Arg *A = Args.getLastArg(OPT_save_optimization_record_passes))
+    Opts.OptRecordPasses = A->getValue();
+
   if (const Arg *A = Args.getLastArg(OPT_save_optimization_record_path))
     Opts.OptRecordFile = A->getValue();