Default to use llvm16

Fix the following error when compiling chromium targeting riscv64 using llvm 10

../../third_party/swiftshader/src/Reactor/LLVMJIT.cpp:796:83: error: no member named 'Create' in 'llvm::jitlink::InProcessMemoryManager'
  796 |             , objectLayer(session, llvm::cantFail(llvm::jitlink::InProcessMemoryManager::Create()))
      |                                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
1 error generated

Change-Id: Ideb0c987dad35ca06b247e18ded6398f313921de
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/73008
Commit-Queue: Shahbaz Youssefi <syoussefi@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@google.com>
Presubmit-Ready: Shahbaz Youssefi <syoussefi@google.com>
Tested-by: Shahbaz Youssefi <syoussefi@google.com>
Reviewed-by: Alexis H├ętu <sugoi@google.com>
diff --git a/src/Reactor/BUILD.gn b/src/Reactor/BUILD.gn
index 67dfeb0..dcb1361 100644
--- a/src/Reactor/BUILD.gn
+++ b/src/Reactor/BUILD.gn
@@ -307,7 +307,7 @@
 
 if (supports_llvm) {
   swiftshader_source_set("swiftshader_llvm_reactor") {
-    llvm_dir = "../../third_party/llvm-10.0"
+    llvm_dir = "../../third_party/llvm-16.0"
 
     deps = [
       ":swiftshader_reactor_base",