C++ code can return values that depend on the storage that backs the
references that were passed in as argument. Thus, swift should not
introdue temporary copies of that storage before invoking those
functions as they could result in lifetime issues.
When we have both const and non-const version of a function, we import
the non-cont version with the "Mutating" suffix. This logic, however, is
redundant for static member functions as those can never be marked as
"const" since they don't have a "self" or "this" to mutate.
rdar://120858502
Fixes https://github.com/apple/swift/issues/66326
This allows us to reneable Windows method tests. Note that Windows still has
a broken convention for non-trivial record with non-trivial destructor but
trivial copy-constructor, so classes in the methods.swift test need an explicit
copy constructor.
Fixes rdar://88391102
