Fix wierd problems linking C programs which look for symbols in libstdc++.

This was due to the 'assert' macro expanding into a function call on some
platforms which could throw.  The C++ compiler then added checks for the
exception specifications in these functions, which pulled in the C++ runtime.
This was bad, and the assertions can never fire (the library is now debugged)
so just remove them.

llvm-svn: 9801