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/libunwindstack/tests/RegsFake.h b/libunwindstack/tests/RegsFake.h
index b81b2ca..8f7d913 100644
--- a/libunwindstack/tests/RegsFake.h
+++ b/libunwindstack/tests/RegsFake.h
@@ -45,7 +45,7 @@
 
   void IterateRegisters(std::function<void(const char*, uint64_t)>) override {}
 
-  bool Format32Bit() { return false; }
+  bool Is32Bit() { return false; }
 
   uint64_t GetAdjustedPc(uint64_t rel_pc, Elf*) override { return rel_pc - 2; }