Cherry-pick PR #38228 into release-3.9 (#38350)

Component commits:
956ac2132a Allowed comment directives to be multiline

12749c9291 Added tests, and perhaps fixed a test runner bug?

99bb366fd6 I think it's going to need a consistent variable to loop over

a21477d6ac Used dynamically computed indexes in verifies

992441d9b8 Added multiline tests

199d256ba2 Increased flexibility for multiline comment parsing

65a7587432 Undid a couple of formatting changes; removed backslashes from multiline regexp

036a4ae922 Merge branch 'master'

b620104be2 Merge branch 'master' of https://github.com/microsoft/TypeScript into multiline-comment-directives

Co-authored-by: Orta Therox <orta.therox@gmail.com>

tests/cases/conformance/directives/multiline.tsx

@@ -0,0 +1,53 @@
+// @filename: a.ts
+export const texts: string[] = [];
+
+/**
+ @ts-ignore */
+texts.push(100);
+
+/**
+ @ts-expect-error */
+texts.push(100);
+
+/**
+ @ts-expect-error */
+texts.push("100");
+
+// @filename: b.tsx
+// @jsx: react
+// @libFiles: react.d.ts,lib.d.ts
+import * as React from "react";
+
+export function MyComponent(props: { foo: string }) {
+  return <div />;
+}
+
+let x = (
+  <div>
+    {/*
+   @ts-ignore */}
+    <MyComponent foo={100} />
+
+    {/*@ts-ignore*/}
+    <MyComponent foo={100} />
+
+    {/*
+   @ts-expect-error */}
+    <MyComponent foo={100} />
+
+    {/*
+   // @ts-expect-error */}
+    <MyComponent foo={100} />
+
+    {/*
+   * @ts-expect-error */}
+    <MyComponent foo={100} />
+
+    {/*@ts-expect-error*/}
+    <MyComponent foo={100} />
+
+    {/*
+   @ts-expect-error */}
+    <MyComponent foo={"hooray"} />
+  </div>
+);

tests/cases/conformance/directives/ts-expect-error.ts

@@ -1,14 +1,32 @@
 // @ts-expect-error additional commenting
-var invalidCommentedFancy: number = 'nope';
+var invalidCommentedFancySingle: number = 'nope';
+
+/*
+ @ts-expect-error additional commenting */
+var invalidCommentedFancyMulti: number = 'nope';
 
 // @ts-expect-error additional commenting
-var validCommentedFancy: string = 'nope';
+var validCommentedFancySingle: string = 'nope';
+
+/* @ts-expect-error additional commenting */
+var validCommentedFancyMulti: string = 'nope';
 
 // @ts-expect-error
-var invalidCommentedPlain: number = 'nope';
+var invalidCommentedPlainSingle: number = 'nope';
+
+/*
+ @ts-expect-error */
+var invalidCommentedPlainMulti: number = 'nope';
 
 // @ts-expect-error
-var validCommentedPlain: string = 'nope';
+var validCommentedPlainSingle: string = 'nope';
+
+/* @ts-expect-error */
+var validCommentedPlainMulti1: string = 'nope';
+
+/*
+@ts-expect-error */
+var validCommentedPlainMulti2: string = 'nope';
 
 var invalidPlain: number = 'nope';