After @rwaldron's feedback:

The purpose of the `!` operator is to evaluate an UnaryExpression,
coerce the result to a boolean value and then return the negated
value of that operation. But that's not what you're trying to do at
all—you just want to evaluate the expression to the right of the
operator, nothing more, nothing less. In this specific case, you
don't even really care about the evaluation, the goal is write
valid (or invalid, as the case may be) syntax that is will be
parsed according to a specific grammar rule that requires some
operator to signal that the thing is an expression and not a Block
Statement.

Ref #822

Fix 850

Authored via the following command:

   $ find test -type f -print0 | \
       xargs -0 sed \
         -i 's/^\(\s*\)negative:\s*SyntaxError\s*$/\1negative:\n\1  phase: early\n\1  type: SyntaxError/g'

Closes #479

Adds tests for the proposal as described here:
http://jeffmo.github.io/es-trailing-function-commas/

Fixes #620

Fixes #477

- lastIndex in RegExp.prototype[Symbol.split]: tc39/ecma262@08b4756747f9c967058239df627da544412740a6
- Missing number conversion in DataView.prototype.setXXX: tc39/ecma262@4f875fe96dcbd5e6363dd3d5b510cd5109199f5b
- Negative zero byteoffset in TypedArray: tc39/ecma262@2d1ed20db778e8f69f66ba76b351b9322fd38495
- EvalDeclarationInstantiation throws TypeError: tc39/ecma262@2be6968715946a4763f6ca8633e311ab7ce63577
- BindingRestElement allows BindingPattern: tc39/ecma262@d322357e6be95bc4bd3e03f5944a736aac55fa50
- Eval in parameters with computed property keys: tc39/ecma262@04e2e9b7197a33612202e85065e3f8d8385fbcef
- Use strict with non-simple parameters: tc39/ecma262@15b0db41edd0e519e94668bf13765fe458840766
- __proto__ in strict mode: tc39/ecma262@5c1984334d6d42538527bd022e68bfbfee5cb652

- RegExp.prototype[Symbol.split] calls ToUint32 (https://github.com/tc39/ecma262/issues/92)
- Species lookup removed from Promise.all and Promise.race (https://github.com/tc39/ecma262/issues/151)
- Generator functions are no longer constructors (https://github.com/tc39/ecma262/pull/171)

Fixes #444

This change set includes tests for most invocations of the
SetFunctionName abstract operation in the ES2015 specification.
Practical testing considerations preclude the introduction of tests for
certain invocations:

- The project is still vetting methods to sustainably test the semantics
  of the Destructuring Binding pattern across all valid productions.
  - 13.3.3.6 Runtime Semantics: IteratorBindingInitialization
  - 13.3.3.7 Runtime Semantics: KeyedBindingInitialization
- Without a loader, there is no way to access a function object declared
  in an ExportDeclaration, so `name` assignment cannot be tested in
  these cases
  - 14.1.19 Runtime Semantics: InstantiateFunctionObject
  - 14.4.12 Runtime Semantics: InstantiateFunctionObject
  - 14.5.15 Runtime Semantics: BindingClassDeclarationEvaluation
  - 15.2.3.11 Runtime Semantics: Evaluation

Update test according to latest change to ES6 spec:
https://twitter.com/awbjs/status/603251578070552576

Avoid extending builtin prototype and consistently define a shadowing
property on the object instance to help recognize a possible
implementation bug.

- in-statement-position-label-statement.js is an Annex-B test (B.3.2 Labelled Function Declarations), moved to annexB directory
- identifier-let-allowed-as-lefthandside-expression-strict.js needs to check for a SyntaxError (ES6, 12.1.1)
- Remove sort() calls in test/built-ins/Object/getOwnPropertyNames/*.js
- Remove sort() calls in test/language/block-scope/syntax/for-in/acquire-properties-from-*.js
- verifyConfigurable() needs to called last in test/built-ins/Object/is/length.js
- All productions within ClassBody are implicitly strict, update test/language/class/method-definition/yield-as-*.js accordingly
- Remove unnecessary noStrict flag in test/language/class/method-definition/yield-as-generator-method-binding-identifier.js
- Check own symbols are returned in property creation order from Object.getOwnPropertySymbols():
  - test/language/computed-property-names/basics/symbol.js
  - test/language/computed-property-names/class/method/symbol.js
  - test/language/computed-property-names/class/static/method-symbol.js
  - test/language/computed-property-names/object/method/symbol.js
- Fix copy-paste error in test/language/expressions/object/method-definition/yield-as-function-expression-binding-identifier.js