swift234

In all cases where playgrounds need to register
classes, UseJIT will also be set, so we don't
need to check.

And there's an important case where we *don't*
need to register classes: testcases, which break
if we do try to register classes, with the
following assertion:

Assertion failed: (registered == c && "objc_readClassPair failed to instantiate the class in-place"), function swift_instantiateObjCClass, file /Volumes/Excelion/swift/lldb-work/llvm/tools/swift/stdlib/runtime/SwiftObject.mm, line 594.

So only register classes if UseJIT is enabled,
and ignore the playground flag.


Swift SVN r20655