Enable multi-threaded Quick compilation

Reuse thread-local copies of llvm context data for Quick compiler
(while continuing to regenerate fresh ones per method for Portable).
This is a transitional CL - the upcoming compiler driver change
is expected to pass pass a thread context structure to each compiler
worker thread rather than use the pthread_key mechanism.

Change-Id: I277920a5c2705748c3a9f37ceace53c903747ec2
diff --git a/src/compiler/Compiler.h b/src/compiler/Compiler.h
index 8bda3fe..7eb32c2 100644
--- a/src/compiler/Compiler.h
+++ b/src/compiler/Compiler.h
@@ -178,10 +178,10 @@
 };
 
 #if defined(ART_USE_QUICK_COMPILER)
-class QuickCompiler {
+class LLVMInfo {
   public:
-    QuickCompiler();
-    ~QuickCompiler();
+    LLVMInfo();
+    ~LLVMInfo();
 
     llvm::LLVMContext* GetLLVMContext() {
       return llvm_context_.get();