Build LSAN suppressions into the test binaries.

This way you don't need to set LSAN_SUPPRESSIONS in your environment...
sort of foolproof this way.

I _think_ the strdup() business from skia:2916 is actually rooted in
libfontconfig, so one suppression should cover both old ones.

I'll leave the file empty until I clean up mention of it in bot recipes.

BUG=skia:2916
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2295153003

CQ_INCLUDE_TRYBOTS=master.client.skia:Test-Ubuntu-Clang-GCE-CPU-AVX2-x86_64-Debug-ASAN-Trybot

Review-Url: https://codereview.chromium.org/2295153003
diff --git a/BUILD.gn b/BUILD.gn
index c86315d..6cb5516 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -653,6 +653,7 @@
       "src/images/SkForceLinking.cpp",
       "src/utils/SkMultiPictureDocumentReader.cpp",  # TODO(halcanary): move to tools?
       "tools/CrashHandler.cpp",
+      "tools/LsanSuppressions.cpp",
       "tools/ProcStats.cpp",
       "tools/Resources.cpp",
       "tools/ThermalManager.cpp",