Switch compile functions to use options structs (#5742)

I've been mulling this mainly for the parameter complexity of
check/lower, but doing lex/parse for symmetry.

I'm motivated by the plan to move dumping for all of them into the
respective functions, because of discussion about llvm-verifier. That
basically would add another bool parameter (or more) to each of these.
My instinct is we're going to probably accrue a little more over time,
so I'm suggesting this as maybe adding the boundary a little simpler
and/or easier to read.

Note it may make sense to refactor a little further, e.g. maybe
Lower::Context could receive the full set of options and pick out what
it wants, but I figured creating the struct itself would be a decent
start.

I'm trying to put things into options when we can produce a reasonable
default if the user doesn't assign a value. I'm using an explicit
constructor so that values can be added without affecting every caller.

A different factoring would be to pass in everything through the param
struct, but that just felt weird when I was trying it out.

Removing `inst_namer` and `module_name` from `LowerToLLVM` params --
both of these can be inferred from `sem_ir`, and I'm not seeing a
particular reason to maintain them at the call site.

toolchain/parse/parse.cpp

@@ -17,11 +17,13 @@ auto HandleInvalid(Context& context) -> void {
                context.PopState());
 }
 
-auto Parse(Lex::TokenizedBuffer& tokens, Diagnostics::Consumer& consumer,
-           llvm::raw_ostream* vlog_stream) -> Tree {
+auto Parse(Lex::TokenizedBuffer& tokens, ParseOptions options) -> Tree {
+  auto* consumer =
+      options.consumer ? options.consumer : &Diagnostics::ConsoleConsumer();
+
   // Delegate to the parser.
   Tree tree(tokens);
-  Context context(&tree, &tokens, &consumer, vlog_stream);
+  Context context(&tree, &tokens, consumer, options.vlog_stream);
   PrettyStackTraceFunction context_dumper(
       [&](llvm::raw_ostream& output) { context.PrintForStackDump(output); });