Remove "dummy" to comply with Android's inclusive language guidance

See https://source.android.com/setup/contribute/respectful-code for reference

Bug: 162536543
Change-Id: I40df639e2f42da6d99d897a02cf05aecff682061
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/307226
Auto-Submit: Leon Scroggins <scroggo@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
diff --git a/src/utils/SkEventTracer.cpp b/src/utils/SkEventTracer.cpp
index 2574306..0a600e9 100644
--- a/src/utils/SkEventTracer.cpp
+++ b/src/utils/SkEventTracer.cpp
@@ -34,8 +34,8 @@
     }
     const char* getCategoryGroupName(
       const uint8_t* categoryEnabledFlag) override {
-        static const char* dummy = "dummy";
-        return dummy;
+        static const char* stub = "stub";
+        return stub;
     }
 };