Also centralizes the knowledge about whether the hashbang is allowed in the
SourceManager. This fixes a bug in tokenize() because previously it just had
to guess.
Swift SVN r6822
around everywhere
Fixes:
rdar://14585108 Code completion does not work at the beginning of the file
rdar://14592634 Code completion returns zero results at EOF in a function
without a closing brace
Swift SVN r6820