Decrease the verbosity of the -ftime-trace option

And move the relevant information in the doc.

Summary:
Currently, building a large software like Firefox shows
'Use chrome://tracing or Speedscope App (https://www.speedscope.app) for flamegraph visualization'
for each file.

Reviewers: anton-afanasyev

Reviewed By: anton-afanasyev

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D68260

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@373308 91177308-0d34-0410-b5e6-96231b3b80d8

docs/ClangCommandLineReference.rst

@@ -1942,7 +1942,8 @@ Perform ThinLTO importing using provided function summary index
 
 .. option:: -ftime-trace
 
-Turn on time profiler
+Turn on time profiler. Results can be analyzed with chrome://tracing or
+`Speedscope App <https://www.speedscope.app>`_ for flamegraph visualization
 
 .. option:: -ftime-trace-granularity=<arg>
 

tools/driver/cc1_main.cpp

@@ -271,9 +271,6 @@ int cc1_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
     llvm::timeTraceProfilerCleanup();
 
     llvm::errs() << "Time trace json-file dumped to " << Path.str() << "\n";
-    llvm::errs()
-        << "Use chrome://tracing or Speedscope App "
-           "(https://www.speedscope.app) for flamegraph visualization\n";
   }
 
   // Our error handler depends on the Diagnostics object, which we're