clang-format: [JS] Allow periods and commata in class declarations

[djasper]

Submitted as r234752.

lib/Format/UnwrappedLineParser.cpp

if (FormatTok->isOneOf(tok::identifier, tok::coloncolon, tok::kw___attribute,
     // We can have macros or attributes in between 'class' and the class name.
     if (FormatTok->Tok.is(tok::l_paren)) {
       parseParens();
     }
     // The actual identifier can be a nested name specifier, and in macros
     // it is often token-pasted.
     while (FormatTok->is(tok::identifier) || FormatTok->is(tok::coloncolon) ||
            FormatTok->is(tok::hashhash) ||
-           (Style.Language == FormatStyle::LK_Java &&
+           ((Style.Language == FormatStyle::LK_Java ||
+             Style.Language == FormatStyle::LK_JavaScript) &&
             FormatTok->isOneOf(tok::period, tok::comma)))
       nextToken();
 
     // Note that parsing away template declarations here leads to incorrectly
     // accepting function declarations as record declarations.
     // In general, we cannot solve this problem. Consider:
     // class A<int> B() {}
     // which can be a function definition or a class definition when B() is a

unittests/Format/FormatTestJS.cpp

 TEST_F(FormatTestJS, ClassDeclarations) {
   verifyFormat("class C {\n  x: string = 12;\n}");
   verifyFormat("class C {\n  x(): string => 12;\n}");
   verifyFormat("class C {\n  ['x' + 2]: string = 12;\n}");
   verifyFormat("class C {\n  private x: string = 12;\n}");
   verifyFormat("class C {\n  private static x: string = 12;\n}");
   verifyFormat("class C {\n  static x(): string { return 'asd'; }\n}");
   verifyFormat("class C extends P implements I {}");
+  verifyFormat("class C extends p.P implements i.I {}");
 }
 
 TEST_F(FormatTestJS, MetadataAnnotations) {
   verifyFormat("@A\nclass C {\n}");
   verifyFormat("@A({arg: 'value'})\nclass C {\n}");
   verifyFormat("@A\n@B\nclass C {\n}");
   verifyFormat("class C {\n  @A x: string;\n}");
   verifyFormat("class C {\n"