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>

src/compiler/utilities.ts

@@ -474,7 +474,7 @@ namespace ts {
     export function createCommentDirectivesMap(sourceFile: SourceFile, commentDirectives: CommentDirective[]): CommentDirectivesMap {
         const directivesByLine = createMapFromEntries(
             commentDirectives.map(commentDirective => ([
-                `${getLineAndCharacterOfPosition(sourceFile, commentDirective.range.pos).line}`,
+                `${getLineAndCharacterOfPosition(sourceFile, commentDirective.range.end).line}`,
                 commentDirective,
             ]))
         );