clang-format: [JS] fix `of` detection.

Summary:
`of` is only a keyword when after an identifier, but not when after
an actual keyword.

Before:
    return of (a, b, c);
After:
    return of(a, b, c);

Reviewers: djasper

Subscribers: cfe-commits, klimek

Differential Revision: https://reviews.llvm.org/D43440

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@325489 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Format/TokenAnnotator.cpp

@@ -2496,7 +2496,7 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
          // (e.g. as "const x of y" in a for loop), or after a destructuring
          // operation (const [x, y] of z, const {a, b} of c).
          (Left.is(Keywords.kw_of) && Left.Previous &&
-          (Left.Previous->Tok.getIdentifierInfo() ||
+          (Left.Previous->Tok.is(tok::identifier) ||
            Left.Previous->isOneOf(tok::r_square, tok::r_brace)))) &&
         (!Left.Previous || !Left.Previous->is(tok::period)))
       return true;

unittests/Format/FormatTestJS.cpp

@@ -294,6 +294,7 @@ TEST_F(FormatTestJS, ReservedWords) {
   verifyFormat("x.for = 1;");
   verifyFormat("x.of();");
   verifyFormat("of(null);");
+  verifyFormat("return of(null);");
   verifyFormat("import {of} from 'x';");
   verifyFormat("x.in();");
   verifyFormat("x.let();");