Include PSTATE in tombstones on arm64.

A thread's PSTATE can sometimes be critical for understanding a crash,
especially with MTE and other new features that store per-thread state
in PSTATE.

Bug: 135772972
Change-Id: I1bee25bffe7eea395f04b6449dc9227298cf866e
diff --git a/libunwindstack/RegsArm64.cpp b/libunwindstack/RegsArm64.cpp
index e9787aa..2e8af20 100644
--- a/libunwindstack/RegsArm64.cpp
+++ b/libunwindstack/RegsArm64.cpp
@@ -103,6 +103,7 @@
   fn("sp", regs_[ARM64_REG_SP]);
   fn("lr", regs_[ARM64_REG_LR]);
   fn("pc", regs_[ARM64_REG_PC]);
+  fn("pst", regs_[ARM64_REG_PSTATE]);
 }
 
 Regs* RegsArm64::Read(void* remote_data) {
@@ -113,6 +114,7 @@
   uint64_t* reg_data = reinterpret_cast<uint64_t*>(regs->RawData());
   reg_data[ARM64_REG_PC] = user->pc;
   reg_data[ARM64_REG_SP] = user->sp;
+  reg_data[ARM64_REG_PSTATE] = user->pstate;
   return regs;
 }