Simplify ASTUnit's internal timers, by not trying to keep a pile of

Simplify ASTUnit's internal timers, by not trying to keep a pile of
timers to be dumped whenever the ASTUnit is destroyed. Instead, just
print the time elapsed for each operation after we perform the
operation.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@117550 91177308-0d34-0410-b5e6-96231b3b80d8