cpplint: Cleanup errors

Cleanup errors from upstream cpplint in preparation
for moving art's cpplint fork to upstream tip-of-tree cpplint.

Test: cd art && mm
Bug: 68951293
Change-Id: I15faed4594cbcb8399850f8bdee39d42c0c5b956
diff --git a/compiler/compiler.h b/compiler/compiler.h
index 6c542c8..cfed6d5 100644
--- a/compiler/compiler.h
+++ b/compiler/compiler.h
@@ -24,12 +24,12 @@
 namespace art {
 
 namespace jit {
-  class JitCodeCache;
-  class JitLogger;
+class JitCodeCache;
+class JitLogger;
 }  // namespace jit
 namespace mirror {
-  class ClassLoader;
-  class DexCache;
+class ClassLoader;
+class DexCache;
 }  // namespace mirror
 
 class ArtMethod;