Revert "Stack maps: Interleave consecutive varints."

This reverts commit a2b34561a7faca95d0a4f8194ad155798e238e37.

Reason for revert: <INSERT REASONING HERE>

Change-Id: Ie5b220e429e101bb5fa2606665a9c8cb64308ad3

Bug: 135638469
diff --git a/runtime/stack_map.h b/runtime/stack_map.h
index b438074..c088eb6 100644
--- a/runtime/stack_map.h
+++ b/runtime/stack_map.h
@@ -443,7 +443,8 @@
 
   ALWAYS_INLINE static QuickMethodFrameInfo DecodeFrameInfo(const uint8_t* code_info_data) {
     BitMemoryReader reader(code_info_data);
-    std::array<uint32_t, kNumHeaders> header = reader.ReadInterleavedVarints<kNumHeaders>();
+    uint32_t header[4];  // flags, packed_frame_size, core_spill_mask, fp_spill_mask.
+    reader.ReadVarints(header);
     return QuickMethodFrameInfo(header[1] * kStackAlignment, header[2], header[3]);
   }