Name boolean arguments in src/compiler.

What would you prefer?

  adaptToMemberWithArgs(tree, qual, name, mode, false, false)

Or:

  adaptToMemberWithArgs(tree, qual, name, mode, reportAmbiguous = false, saveErrors = false)
Name boolean arguments in src/reflect.
Name boolean arguments in src/library.
Check named-args-for-clarity incur no extra bytecode

When named arguments correspond the the parameter declaration
order, the compiler should not lift out assignments before
the method call, as it would have to do for out-of-order
arguments.

Confirm this with a bytecode comparison test.
Merge pull request #2203 from paulp/topic/bool-arg-rebased

Name boolean arguments (rebased)