Switch Chromium/Fuchsia to use the LLVM ORCv2 JIT

Most of Chromium uses Subzero as the JIT backend for Reactor, but
Fuchsia on ARM64 uses LLVM, which previously broke when switching to
ORCv2 due to LLVM_ENABLE_ABI_BREAKING_CHECKS being set inconsistently
https://swiftshader-review.googlesource.com/c/SwiftShader/+/49908

Bug: b/171897980
Bug: chromium:1140854
Change-Id: I4ab3422387fa966fb76fb90b27532630de69594a
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/49852
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
diff --git a/src/Reactor/BUILD.gn b/src/Reactor/BUILD.gn
index cce2400..eedc36c 100644
--- a/src/Reactor/BUILD.gn
+++ b/src/Reactor/BUILD.gn
@@ -329,7 +329,7 @@
 
     sources = [
       "CPUID.cpp",
-      "LLVMJIT_ORCv1.cpp",  # TODO(b/171897980): Upgrade to ORCv2
+      "LLVMJIT.cpp",
       "LLVMReactor.cpp",
     ]