Improvements to unique_file and createUniqueDirectory.
* Don't try to create parent directories in unique_file. It had two problem:
* It violates the contract that it is atomic. If the directory creation
success and the file creation fails, we would return an error but the
file system was modified.
* When creating a temporary file clang would have to first check if the
parent directory existed or not to avoid creating one when it was not
supposed to.
* More efficient implementations of createUniqueDirectory and the unique_file
that produces only the file name. Now all 3 just call into a static
function passing what they want (name, file or directory).
Clang also has to be updated, so tests might fail if a bot picks up this commit
and not the corresponding clang one.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185126
91177308-0d34-0410-b5e6-
96231b3b80d8