swift234

This fixes a bot failure in the LLDB testsuite.

This removes an assertion that no longer serves its purpose and
relaxes the IRBuilder checks for debug info when generating code
inside the debugger.

When LLDB is JIT-compiling expressions, it will not generate a
SWIFT_ENTRY_POINT_FUNCTION (there will be one per expression)
but it will still generate the equivalent of top level code.

rdar://problem/26955467