pp-trace - preprocessor tacing and PPCallbacks testing tool

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@193743 91177308-0d34-0410-b5e6-96231b3b80d8
check-clang-tools: Reorder CLANG_TOOLS_TEST_DEPS.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@193744 91177308-0d34-0410-b5e6-96231b3b80d8
check-clang-tools: Add pp-trace for deps.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@193745 91177308-0d34-0410-b5e6-96231b3b80d8
Fix comment. pp-trace can only handle source file at a time.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@193746 91177308-0d34-0410-b5e6-96231b3b80d8