[copybara-service]

Enforce @MustBeClosed on method and constructor references.

MustBeClosedChecker only checked method invocations and constructor calls, so
passing a reference to a @MustBeClosed method or constructor (such as
foo::mustBeClosedMethod or MustBeClosedResource::new) to a functional
interface whose method is not annotated with @MustBeClosed (such as
Supplier<Closeable>) bypassed the check and let the resource leak.

Method and constructor references are now checked like lambdas: they are
reported unless the functional interface method is annotated with
@MustBeClosed. As with lambdas, references passed to exception-testing APIs
such as assertThrows are exempt. StreamResourceLeak shares this logic, so it
now also reports references such as Files::lines. The new behavior can be
disabled with -XepOpt:MustBeClosedChecker:MatchMethodReferences=false.