Partially revert r204517 and fix a different way:

We don't want to encourage the code to emit a lexical block for
a function that needs one in order for the line table to change,
we need to grab the line information from the body of the pattern
that we were instantiated from, this code should do that.

Modify the test case to ensure that we're still looking in the
right place for all of the scopes and also that we haven't
created a lexical block where we didn't need one.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@205368 91177308-0d34-0410-b5e6-96231b3b80d8