Add assert messages

Add necessary asserts

format cc1_main.cpp

Restyle codes

format code

In D131469#3715929, @jamieschmeiser wrote:

You should not have debugging information in code that is up for review. If this is debugging information that you plan to leave in for future purposes (which I doubt is the case here), you need to protect it so that it isn't active unless some option is set. For example, see LLVM_DEBUG code that lives in various opt routines.

fix stringRef bug

Add more debug info

Add more debug info

[Clang] add -### for debug

[Clang] fix mkdir error in ftime-trace=<value> test

[Clang] restyle code

[Clang] format the source file

[Clang] change test cases to different directory

Hi @jamieschmeiser @Whitney @MaskRay, I have changed "-ftime-trace-path" to "-ftime-trace". It is a well-spelling option name.

[Clang] change "-ftime-trace-path" to "-ftime-trace"

[Clang] rewrite test case of "-ftime-trace-path"

I have changed the approach from directory-store to path-store, so that the user can specify the aim path to store the time trace json file.
If "-ftime-trace-path" is not specified, it will follow the default behavior.

[Clang] change directory-store to path-store

In D128048#3601579, @jamieschmeiser wrote:

Can you please use git rebase -i to collapse all the changes into a single change? If this isn't done, it is difficult to know what is being reviewed as the changes only show the differences since your last revision, not all of the changes.

[Clang] update help text of "ftime-trace-path"

In D128048#3591829, @Whitney wrote:

Can you please add some test cases?

[Clang] change unclear help text pf "-ftime-trace-path"

[Clang] Restore the old behaviors when "-ftime-trace-path" is not specified