fix(compiler-cli): Pass SourceFile to getLeadingTriviaWidth (#33588)

This commit fixes a crash in the Angular Kythe indexer caused by failure
to retrieve `SourceFile` in a `Statement`.

Crash logs:
  TypeError: Cannot read property 'text' of undefined
    at Object.getTokenPosOfNode (typescript/stable/lib/typescript.js:8957:72)
    at NodeObject.getStart (typescript/stable/lib/typescript.js:121419:23)
    at NodeObject.getLeadingTriviaWidth (typescript/stable/lib/typescript.js:121439:25)
    at FactoryGenerator.generate (angular2/rc/packages/compiler-cli/src/ngtsc/shims/src/factory_generator.ts:64:49)
    at GeneratedShimsHostWrapper.getSourceFile (angular2/rc/packages/compiler-cli/src/ngtsc/shims/src/host.ts:88:26)
    at findSourceFile (typescript/stable/lib/typescript.js:90654:29)
    at typescript/stable/lib/typescript.js:90553:85
    at getSourceFileFromReferenceWorker (typescript/stable/lib/typescript.js:90520:34)
    at processSourceFile (typescript/stable/lib/typescript.js:90553:13)
    at processRootFile (typescript/stable/lib/typescript.js:90383:13)

PR Close #33588

packages/compiler-cli/src/ngtsc/shims/src/factory_generator.ts

@@ -59,8 +59,12 @@ export class FactoryGenerator implements ShimGenerator {
     let comment: string = '';
     if (original.statements.length > 0) {
       const firstStatement = original.statements[0];
-      if (firstStatement.getLeadingTriviaWidth() > 0) {
-        comment = firstStatement.getFullText().substr(0, firstStatement.getLeadingTriviaWidth());
+      // Must pass SourceFile to getLeadingTriviaWidth(), otherwise it'll try to
+      // get SourceFile by recursively looking up the parent of the Node and fail,
+      // because parent is undefined.
+      const leadingTriviaWidth = firstStatement.getLeadingTriviaWidth(original);
+      if (leadingTriviaWidth > 0) {
+        comment = firstStatement.getFullText().substr(0, leadingTriviaWidth);
       }
     }