Add ability to read jit gdb data.

Changes:
- New JitDebug class to handle all of the jit gdb interface.
- Add unit tests for all, along with new offline test using debug data.
- Add new Memory type called MemoryOfflineParts that has multiple
  MemoryOffline objects to support the offline test.
- Update the tools to use the JitDebug object.
- Modify libbacktrace to use the JitDebug, but only looking in libart.so
  and libartd.so.
- Change the Format32Bits to Is32Bit since it's more accurate and I use
  it in a different context where original name didn't make sense.
- Add a new function to find global variables in an elf file
  (GetGlobalVariable).
- Add a new function to determine if a pc is valid for this elf (IsValidPc).

Bug: 68396769

Test: Ran new unit tests. Added new offline test that uses jit debug data.
Test: Ran art test that generates jit data and verified a crash unwinds
Test: through the jit data.
Change-Id: I6e7ee2f5bab2242028a06feece156dff21c0a974
diff --git a/libbacktrace/UnwindStackMap.cpp b/libbacktrace/UnwindStackMap.cpp
index 836a774..93406dc 100644
--- a/libbacktrace/UnwindStackMap.cpp
+++ b/libbacktrace/UnwindStackMap.cpp
@@ -18,6 +18,9 @@
 #include <stdlib.h>
 #include <sys/types.h>
 
+#include <string>
+#include <vector>
+
 #include <backtrace/BacktraceMap.h>
 #include <unwindstack/Elf.h>
 #include <unwindstack/MapInfo.h>
@@ -39,6 +42,10 @@
   // Create the process memory object.
   process_memory_ = unwindstack::Memory::CreateProcessMemory(pid_);
 
+  // Create a JitDebug object for getting jit unwind information.
+  std::vector<std::string> search_libs_{"libart.so", "libartd.so"};
+  jit_debug_.reset(new unwindstack::JitDebug(process_memory_, search_libs_));
+
   if (!stack_maps_->Parse()) {
     return false;
   }