Make arm32 cpu detection recognize the DragonBoard as arm64.

runtime/vm/cpuinfo_android.cc

Index: runtime/vm/cpuinfo_android.cc
diff --git a/runtime/vm/cpuinfo_android.cc b/runtime/vm/cpuinfo_android.cc
index 1e4229ca5a0ed59ca812de6a398775839bea53ad..077de16107b078f6d41218af3ee7c3c304cd3616 100644
--- a/runtime/vm/cpuinfo_android.cc
+++ b/runtime/vm/cpuinfo_android.cc
@@ -25,16 +25,19 @@ void CpuInfo::InitOnce() {
   fields_[kCpuInfoModel] = "model name";
   fields_[kCpuInfoHardware] = "model name";
   fields_[kCpuInfoFeatures] = "flags";
+  fields_[kCpuInfoArchitecture] = "CPU architecture";
 #elif defined(HOST_ARCH_ARM) || defined(HOST_ARCH_ARM64)
   fields_[kCpuInfoProcessor] = "Processor";
   fields_[kCpuInfoModel] = "model name";
   fields_[kCpuInfoHardware] = "Hardware";
   fields_[kCpuInfoFeatures] = "Features";
+  fields_[kCpuInfoArchitecture] = "CPU architecture";
 #elif defined(HOST_ARCH_MIPS)
   fields_[kCpuInfoProcessor] = "system type";
   fields_[kCpuInfoModel] = "cpu model";
   fields_[kCpuInfoHardware] = "cpu model";
   fields_[kCpuInfoFeatures] = "ASEs implemented";
+  fields_[kCpuInfoArchitecture] = "CPU architecture";
 #else
 #error Unrecognized target architecture
 #endif