Implements breaking of string literals if they stick out.

An alternative strategy to calculating the break on demand when hitting
a token that would need to be broken would be to put all possible breaks
inside the token into the optimizer.

Currently only supports breaking at spaces; more break points to come.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175613 91177308-0d34-0410-b5e6-96231b3b80d8