Remove wrong and unnecessary assertion.

PHIs are allowed to have multiple operand pairs per predecessor, and
this code works just fine when it happens.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176734 91177308-0d34-0410-b5e6-96231b3b80d8
Don't emit the extra checksum into the .gcda file if the user hasn't asked for
it. Fortunately, versions of gcov that predate the extra checksum also ignore
any extra data, so this isn't a problem. There will be a matching commit in
compiler-rt.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176745 91177308-0d34-0410-b5e6-96231b3b80d8