Fix bug in ParallelMoveResolver::EmitSwap: implement swaps of FPU spill slots.

runtime/vm/flow_graph_compiler_mips.cc

Index: runtime/vm/flow_graph_compiler_mips.cc
diff --git a/runtime/vm/flow_graph_compiler_mips.cc b/runtime/vm/flow_graph_compiler_mips.cc
index 1e45e76d81be62097131636d1e2ff259ef4ccf68..06c56e31fac1dc4c3e11993b38c7161fb94b3c24 100644
--- a/runtime/vm/flow_graph_compiler_mips.cc
+++ b/runtime/vm/flow_graph_compiler_mips.cc
@@ -1100,6 +1100,26 @@ void ParallelMoveResolver::Exchange(const Address& mem1, const Address& mem2) {
 }
 
 
+void ParallelMoveResolver::SpillScratch(Register reg) {
+  UNIMPLEMENTED();
+}
+
+
+void ParallelMoveResolver::RestoreScratch(Register reg) {
+  UNIMPLEMENTED();
+}
+
+
+void ParallelMoveResolver::SpillFpuScratch(FpuRegister reg) {
+  UNIMPLEMENTED();
+}
+
+
+void ParallelMoveResolver::RestoreFpuScratch(FpuRegister reg) {
+  UNIMPLEMENTED();
+}
+
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS