Print more info in MarkSweep::VerifyRoot

Refactored old root callback to use a new class called RootInfo.
RootInfo contains all the relevant info related to the root
associated with the callback. The MarkSweep::VerifyRoot function
now uses this info to print the StackVisitor's described location
if the GC root is of the type kRootJavaFrame.

Some other cleanup.

Example output:
E/art     (12167): Tried to mark 0x123 not contained by any spaces
E/art     (12167): Attempting see if it's a bad root
E/art     (12167): Found invalid root: 0x123 with type RootJavaFrame
E/art     (12167): Location=Visiting method
'void java.lang.Runtime.gc()' at dex PC 0xffffffff (native PC 0x0)
vreg=0

(cherry picked from commit 12f7423a2bb4bfab76700d84eb6d4338d211983a)

Bug: 18588862
Change-Id: Ic5a2781f704e931265ffb3621c2eab4b2e25f60f
diff --git a/runtime/gc/collector/semi_space.cc b/runtime/gc/collector/semi_space.cc
index 82d6992..fcc601f 100644
--- a/runtime/gc/collector/semi_space.cc
+++ b/runtime/gc/collector/semi_space.cc
@@ -600,8 +600,7 @@
   reinterpret_cast<SemiSpace*>(arg)->DelayReferenceReferent(klass, ref);
 }
 
-void SemiSpace::MarkRootCallback(Object** root, void* arg, uint32_t /*thread_id*/,
-                                 RootType /*root_type*/) {
+void SemiSpace::MarkRootCallback(Object** root, void* arg, const RootInfo& /*root_info*/) {
   auto ref = StackReference<mirror::Object>::FromMirrorPtr(*root);
   reinterpret_cast<SemiSpace*>(arg)->MarkObject(&ref);
   if (*root != ref.AsMirrorPtr()) {