swiftshader: llvm-16.0: remove unnecessary virtual specifier

With ag/37181443, this worked around this in Mesa.  But not
we generate Android.bp automatically, so we either need to
upstream a patch to Mesa3D that explains this LLVM 16 quirk,
or we just modify Swiftshader LLVM.

Since Swiftshader is on it's way out and the chances of
merge conflicts is very small, workaround it here.

BUG=473596493
TEST=CI/CD

Change-Id: Idb306ddef1a73d777f4050ea2e1e6928aebcfb26
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/77168
Tested-by: Geoff Lang <geofflang@google.com>
Reviewed-by: Geoff Lang <geofflang@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@google.com>
Commit-Queue: Geoff Lang <geofflang@google.com>

third_party/llvm-16.0/llvm/include/llvm/IR/ConstantFolder.h

diff --git a/third_party/llvm-16.0/llvm/include/llvm/IR/ConstantFolder.h b/third_party/llvm-16.0/llvm/include/llvm/IR/ConstantFolder.h
index 82c07d4..1680edd 100644
--- a/third_party/llvm-16.0/llvm/include/llvm/IR/ConstantFolder.h
+++ b/third_party/llvm-16.0/llvm/include/llvm/IR/ConstantFolder.h
@@ -28,7 +28,7 @@
 
 /// ConstantFolder - Create constants with minimum, target independent, folding.
 class ConstantFolder final : public IRBuilderFolder {
-  virtual void anchor();
+  void anchor();
 
 public:
   explicit ConstantFolder() = default;