Add VMRuntime.isBootClassPathOnDisk

Bug: 17679443

(cherry picked from commit 95a935415d44903b28326424beb4db5c013ef089)

Change-Id: Iba40291dead3f0b6715903c986370fd0cf1e41e1
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 2cf3820..6ed27bb 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -1179,7 +1179,7 @@
   uint32_t image_oat_checksum = 0;
   uintptr_t image_oat_data_begin = 0;
   int32_t image_patch_delta = 0;
-  if (instruction_set == Runtime::Current()->GetInstructionSet()) {
+  if (instruction_set == runtime->GetInstructionSet()) {
     const ImageHeader& image_header = image_space->GetImageHeader();
     image_oat_checksum = image_header.GetOatChecksum();
     image_oat_data_begin = reinterpret_cast<uintptr_t>(image_header.GetOatDataBegin());