Appease valgrind wrt testing code initialization

The new swarming valgrind bot appears to be higher maintenance. These changes seem harmless and will, hopefully, unblock the bot.

TBR=bsalomon@google.com

https://build.chromium.org/p/client.skia.fyi/builders/Test-Ubuntu-GCC-ShuttleA-GPU-GTX550Ti-x86_64-Release-SwarmingValgrind/builds/57

BUG=skia:5164
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1867053002

Review URL: https://codereview.chromium.org/1867053002
diff --git a/tests/PathOpsSimplifyRectThreadedTest.cpp b/tests/PathOpsSimplifyRectThreadedTest.cpp
index 8c4e03c..7289440 100644
--- a/tests/PathOpsSimplifyRectThreadedTest.cpp
+++ b/tests/PathOpsSimplifyRectThreadedTest.cpp
@@ -42,7 +42,8 @@
         SkPath path, out;
         char* str = pathStr;
         path.setFillType(SkPath::kWinding_FillType);
-        int l, t, r, b;
+        int l SK_INIT_TO_AVOID_WARNING, t SK_INIT_TO_AVOID_WARNING,
+            r SK_INIT_TO_AVOID_WARNING, b SK_INIT_TO_AVOID_WARNING;
         if (aShape) {
             switch (aShape) {
                 case 1:  // square