Previously, it was possible for $main to be made dynamic by passing
-enable-implicit-dynamic. That has always been a problem in asserts
builds because a direct function_ref to $main is created in the main
function. More recently, it has become a problem in non-asserts builds
because the dynamic replacements are now in the IR module but are not in
the TBD file.
Here, the function is marked as not dynamic.
rdar://84962693
