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/lex/tokenized_buffer_fuzzer.cpp

@@ -35,7 +35,9 @@ extern "C" int LLVMFuzzerTestOneInput(const unsigned char* data, size_t size) {
       SourceBuffer::MakeFromFile(fs, TestFileName, Diagnostics::NullConsumer());
 
   SharedValueStores value_stores;
-  auto buffer = Lex::Lex(value_stores, *source, Diagnostics::NullConsumer());
+  Lex::LexOptions options;
+  options.consumer = &Diagnostics::NullConsumer();
+  auto buffer = Lex::Lex(value_stores, *source, options);
   if (buffer.has_errors()) {
     return 0;
   }