spirv-reader: Remove stale TODO

Change-Id: Icd9bf067160c7b79b3c5d8c3123ac94a8f29376c
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/48400
Reviewed-by: David Neto <dneto@google.com>
Reviewed-by: Alan Baker <alanbaker@google.com>
Auto-Submit: David Neto <dneto@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Alan Baker <alanbaker@google.com>
diff --git a/src/reader/spirv/function.cc b/src/reader/spirv/function.cc
index 7e6608f..1f9a48e 100644
--- a/src/reader/spirv/function.cc
+++ b/src/reader/spirv/function.cc
@@ -3370,8 +3370,6 @@
   //    OpPtrCastToGeneric // Not in Vulkan
   //    OpGenericCastToPtr // Not in Vulkan
   //    OpGenericCastToPtrExplicit // Not in Vulkan
-  //
-  //    OpArrayLength
 
   return {};
 }