Revert of [Compiler] Track Ignition background compilation separately in RuntimeStats.

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index 63e48d2fb3741a8cf52f86d899d1726397c6e5c1..e7110fe36a74185e830cfa3543fc28b0e47ff64f 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -167,8 +167,7 @@
       : info_(info),
         compiler_name_(compiler_name),
         state_(initial_state),
-        stack_limit_(isolate->stack_guard()->real_climit()),
-        executed_on_background_thread_(false) {}
+        stack_limit_(isolate->stack_guard()->real_climit()) {}
   virtual ~CompilationJob() {}
 
   // Prepare the compile job. Must be called on the main thread.
@@ -197,11 +196,6 @@
   void set_stack_limit(uintptr_t stack_limit) { stack_limit_ = stack_limit; }
   uintptr_t stack_limit() const { return stack_limit_; }
 
-  bool executed_on_background_thread() const {
-    DCHECK_IMPLIES(!can_execute_on_background_thread(),
-                   !executed_on_background_thread_);
-    return executed_on_background_thread_;
-  }
   State state() const { return state_; }
   CompilationInfo* info() const { return info_; }
   Isolate* isolate() const;
@@ -224,7 +218,6 @@
   const char* compiler_name_;
   State state_;
   uintptr_t stack_limit_;
-  bool executed_on_background_thread_;
 
   MUST_USE_RESULT Status UpdateState(Status status, State next_state) {
     if (status == SUCCEEDED) {