Add a few profraw files in gitignore

These files are generated while running tests. They are generated here:
https://source.chromium.org/chromium/chromium/src/+/main:content/common/profiling_utils.cc;l=76;drc=b317893a6b79e793239efe7c9455e210b478720f

Change-Id: I02eb5f5853c419fbddb779db7da00a9cd33e7bd6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3628489
Commit-Queue: Sven Zheng <svenzheng@chromium.org>
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1000099}

.gitignore

@@ -53,6 +53,11 @@
 *.class
 compile_commands.json
 cscope.*
+child_pool-0.profraw
+child_pool-1.profraw
+child_pool-2.profraw
+child_pool-3.profraw
+default.profraw
 GPATH
 GRTAGS
 GSYMS