Fix GN build

Add missing comma, introduced in 9c14bda072c9882c9b7f56bc9b397a9ec3c8d364

Bug: none
Change-Id: Iffbe771b6c6af408c2c809e9beef694543554aa4
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/48748
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Antonio Maiorano <amaiorano@google.com>
diff --git a/src/Reactor/BUILD.gn b/src/Reactor/BUILD.gn
index 71c98e0..eedc36c 100644
--- a/src/Reactor/BUILD.gn
+++ b/src/Reactor/BUILD.gn
@@ -49,7 +49,7 @@
     "Debug.cpp",
     "EmulatedIntrinsics.cpp",
     "ExecutableMemory.cpp",
-    "OptimalIntrinsics.cpp"
+    "OptimalIntrinsics.cpp",
     "Reactor.cpp",
   ]
 }