Remove infinite recursion due to FileSpec change.
Remove infinite recursion due to FileSpec change.

Fixes infinite recursion due to change in how FileSpec deals with
removing the last path component.

Fixes timout for TestMiniDumpNew.py

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@333666 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 9f2521522ea0402e16e06038269679a7c0f6c17e)
(cherry picked from commit e8be40ae461bd7948429ebc5bfc4423f2c30bde2)

apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb