Revert "Add one LinearAlloc per ClassLoader"

Times out on 32bit target/host for 132-daemon-locks-shutdown test.

Bug: 22720414

This reverts commit 356412e2b7ba3fde164bc08a44fee0ddc19c54e1.

Change-Id: I5ab3a09e88a5ad8c306a27d2606ecbecc80b9326
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index ccfc4bc..6b144cf 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -944,8 +944,10 @@
   if (IsCompiler() && Is64BitInstructionSet(kRuntimeISA)) {
     // 4gb, no malloc. Explanation in header.
     low_4gb_arena_pool_.reset(new ArenaPool(false, true));
+    linear_alloc_.reset(new LinearAlloc(low_4gb_arena_pool_.get()));
+  } else {
+    linear_alloc_.reset(new LinearAlloc(arena_pool_.get()));
   }
-  linear_alloc_.reset(CreateLinearAlloc());
 
   BlockSignals();
   InitPlatformSignalHandlers();
@@ -1786,10 +1788,4 @@
   return verify_ == verifier::VerifyMode::kSoftFail;
 }
 
-LinearAlloc* Runtime::CreateLinearAlloc() {
-  return (IsCompiler() && Is64BitInstructionSet(kRuntimeISA))
-      ? new LinearAlloc(low_4gb_arena_pool_.get())
-      : new LinearAlloc(arena_pool_.get());
-}
-
 }  // namespace art