Line breakpoints for await

Running test: testAwaitInAsyncFunctionWithLeadingWhitespace
Setting breakpoint on `await this.foo()` in `obj.bar`
Calling `obj.bar()`
Hit breakpoint before calling into `this.foo`

Running test: testAwaitInAsyncFunctionWithoutLeadingWhitespace
Setting breakpoint on `await this.foo()` in `obj.baz`
Calling `obj.baz()`
Hit breakpoint before calling into `this.foo`

Running test: testAwaitInAsyncGeneratorWithLeadingWhitespace
Setting breakpoint on `await this.foo()` in `obj.barGenerator`
Calling `obj.barGenerator().next()`
Hit breakpoint before calling into `this.foo`

Running test: testAwaitInAsyncGeneratorWithoutLeadingWhitespace
Setting breakpoint on `await this.foo()` in `obj.bazGenerator`
Calling `obj.bazGenerator().next()`
Hit breakpoint before calling into `this.foo`

Running test: testAwaitInAsyncFunctionMinified
Setting breakpoint on `await this.foo()` in `obj.minified`
Calling `obj.minified()`
Hit breakpoint before calling into `this.foo`