[be] Move Result into Utils/

The `Utils/` folder is meant to be a catch-all for code that doesn't have an 
obvious home in other directories.

compiler/forget/src/HIR/BuildHIR.ts

@@ -9,7 +9,7 @@ import { NodePath, Scope } from "@babel/traverse";
 import * as t from "@babel/types";
 import invariant from "invariant";
 import { CompilerError, ErrorSeverity } from "../CompilerError";
-import { Err, Ok, Result } from "../lib/Result";
+import { Err, Ok, Result } from "../Utils/Result";
 import { assertExhaustive } from "../Utils/utils";
 import {
   BlockId,

compiler/forget/src/__tests__/Result-test.ts

@@ -1,4 +1,4 @@
-import { Err, Ok, Result } from "../lib/Result";
+import { Err, Ok, Result } from "../Utils/Result";
 
 function addMax10(a: number, b: number): Result<number, string> {
   const n = a + b;