Revert^2 "Refactor code around JIT creation."

This reverts commit 763cd98161424cf19af2f113a6802f04860dcd6e.

Bug: 119800099

Reason for revert: Updated the DCHECKo take into account current state
of zygote not having a thread pool.

Change-Id: I1181ff85e7aebd062ee892548b80ab3de06a5ac7
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index ce7dfaf..bcc05c7 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -3145,7 +3145,7 @@
     return (jit == nullptr) || !jit->GetCodeCache()->ContainsPc(quick_code);
   }
 
-  if (runtime->IsNativeDebuggableZygoteOK()) {
+  if (runtime->IsNativeDebuggable()) {
     DCHECK(runtime->UseJitCompilation() && runtime->GetJit()->JitAtFirstUse());
     // If we are doing native debugging, ignore application's AOT code,
     // since we want to JIT it (at first use) with extra stackmaps for native