compiler, runtime: Begin Runtime Refactor

Ultimately, the goal is to completely separate the compilation from
the runtime to make it possible to have the interpreter/evaluator
be "just another" entity that can perform meaningful work when
given a parsed GP4 program.

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

Tests/p4rseTests/ParserCompilerTests.swift

@@ -95,7 +95,7 @@ import P4Lang
   let result = try! #require(p.parse(simple))
 
   #expect(
-    #RequireErrorResult<(EvaluatableStatement, CompilerContext)>(
+    #RequireErrorResult<ParserAssignmentStatement>(
       ErrorWithLocation(sourceLocation: SourceLocation(2, 154), withError: "Did not find assignment statement"),
       ParserAssignmentStatement.Compile( // Note: Calling ParserAssignmentStatement compilation directly.
         node: result.rootNode!, withContext: CompilerContext())))
@@ -182,3 +182,16 @@ import P4Lang
 
   #expect(#RequireOkResult(SpecialCompilers.ProgramCompiler.Compile(simple)))
 }
+
+@Test func test_simple_compiler_with_instantiation() async throws {
+    let simple_instantiation_program = """
+        parser MainParser() {
+            state start {
+                transition accept;
+            }
+        };
+
+        MainParser() mp;
+    """
+  #expect(#RequireOkResult(SpecialCompilers.ProgramCompiler.Compile(simple_instantiation_program)))
+}