Change ConcurrentMap::setLocked() to take a const K& instead of K&&.

This allows const qualification to be implicitly added to pointers when
converting them to the type of setLocked()'s first argument (this implicit
conversion was for example being done here: [1]). Previously this was allowed,
but a standards wording change adopted in newer versions of clang caused
this to become forbidden. See [2] for details.

The std::forward that was previously being applied to the first argument
now has no effect, so it has been removed.

[1] https://cs.android.com/android/platform/superproject/+/master:system/libhidl/transport/HidlBinderSupport.cpp;l=247
[2] http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20191223/299934.html

Bug: 145916209
Change-Id: Id5aac7805ad2944f019cadc87159aaf817c3e3e4
1 file changed