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/testing/compile_helper.cpp

@@ -15,8 +15,10 @@ auto CompileHelper::GetTokenizedBuffer(llvm::StringRef text,
   auto& source = GetSourceBuffer(text);
 
   value_store_storage_.emplace_front();
-  token_storage_.push_front(Lex::Lex(value_store_storage_.front(), source,
-                                     consumer ? *consumer : consumer_));
+  Lex::LexOptions options;
+  options.consumer = consumer ? consumer : &consumer_;
+  token_storage_.push_front(
+      Lex::Lex(value_store_storage_.front(), source, options));
   return token_storage_.front();
 }
 
@@ -29,8 +31,9 @@ auto CompileHelper::GetTokenizedBufferWithSharedValueStore(
 
 auto CompileHelper::GetTree(llvm::StringRef text) -> Parse::Tree& {
   auto& tokens = GetTokenizedBuffer(text);
-  tree_storage_.push_front(Parse::Parse(tokens, consumer_,
-                                        /*vlog_stream=*/nullptr));
+  Parse::ParseOptions options;
+  options.consumer = &consumer_;
+  tree_storage_.push_front(Parse::Parse(tokens, options));
   return tree_storage_.front();
 }