ART: Remember whether the cache was pruned

Remember (and expose) whether the cache was pruned when initializing
the runtime.

Bug: 27618311

(cherry picked from commit 7ef1b4b20bd7cf485f5e443927c1e6fa797a0439)

Change-Id: I178d18d731a9dce5cb11ed0874c9c9c9d36d7d8e
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index 0dfb0cf..66a3828 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -208,7 +208,8 @@
       experimental_flags_(ExperimentalFlags::kNone),
       oat_file_manager_(nullptr),
       is_low_memory_mode_(false),
-      safe_mode_(false) {
+      safe_mode_(false),
+      pruned_dalvik_cache_(false) {
   CheckAsmSupportOffsetsAndSizes();
   std::fill(callee_save_methods_, callee_save_methods_ + arraysize(callee_save_methods_), 0u);
   interpreter::CheckInterpreterAsmConstants();