[Build] Use -ftime-trace instead of -ftime-report.

-ftime-report prints buggy, not-too-informative tables to stdout
while -ftime-trace creates .json files for each translation unit
that can be loaded into chrome://tracing, and offers much more
useful information about e.g. how much time is spent on
creating code for or optimizing specific functions.

      files generated next to the .o files in chrome://tracing

Bug: None
Test: Turn compiler_timing on, build a target, load the .json
Change-Id: I6380c10bd94f151f20d5909676d89d0b70ee453b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1661714Reviewed-by: Reid Kleckner <rnk@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#669714}

build/config/compiler/BUILD.gn

@@ -658,9 +658,9 @@ config("compiler") {
   if (compiler_timing) {
     if (is_clang) {
       if (is_win) {
-        cflags += [ "/clang:-ftime-report" ]
+        cflags += [ "/clang:-ftime-trace" ]
       } else {
-        cflags += [ "-ftime-report" ]
+        cflags += [ "-ftime-trace" ]
       }
     } else if (is_win) {
       cflags += [
@@ -1092,7 +1092,8 @@ config("compiler_deterministic") {
   }
 
   # Makes builds independent of absolute file path.
-  if (symbol_level != 0 && is_clang && strip_absolute_paths_from_debug_symbols) {
+  if (symbol_level != 0 && is_clang &&
+      strip_absolute_paths_from_debug_symbols) {
     # If debug option is given, clang includes $cwd in debug info by default.
     # For such build, this flag generates reproducible obj files even we use
     # different build directory like "out/feature_a" and "out/feature_b" if