Allow for multiple method parameters to be @MustCallAlias in Resource Leak Checker

[msridhar]

(moving from kelloggm/object-construction-checker#409)

Right now, the Resource Leak Checker only supports writing @MustCallAlias on one formal parameter of a method, but we should generalize this. Consider SequenceInputStream:

https://docs.oracle.com/javase/7/docs/api/java/io/SequenceInputStream.html

For the Resource Leak Checker, I believe the correct qualifiers for this class are:

• @MustCall({}) for the class
• @MustCallAlias for both formal parameters of the SequenceInputStream(InputStream s1, InputStream s2) constructor

I believe the semantics are clear; when that constructor is invoked, the returned SequenceInputStream is a resource alias for both s1 and s2, and closing the SequenceInputStream will close both s1 and s2. I do not believe it will be terribly difficult to add support for this pattern to the checker.