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.h b/libbacktrace/UnwindStackMap.h
index 2f63655..12c5909 100644
--- a/libbacktrace/UnwindStackMap.h
+++ b/libbacktrace/UnwindStackMap.h
@@ -23,6 +23,7 @@
 #include <memory>
 
 #include <backtrace/BacktraceMap.h>
+#include <unwindstack/JitDebug.h>
 #include <unwindstack/Maps.h>
 
 class UnwindStackMap : public BacktraceMap {
@@ -41,11 +42,14 @@
 
   const std::shared_ptr<unwindstack::Memory>& process_memory() { return process_memory_; }
 
+  unwindstack::JitDebug* GetJitDebug() { return jit_debug_.get(); }
+
  protected:
   uint64_t GetLoadBias(size_t index) override;
 
   std::unique_ptr<unwindstack::Maps> stack_maps_;
   std::shared_ptr<unwindstack::Memory> process_memory_;
+  std::unique_ptr<unwindstack::JitDebug> jit_debug_;
 };
 
 #endif  // _LIBBACKTRACE_UNWINDSTACK_MAP_H