[asm.js] (Re)use temporaries in asm->wasm conversion.

src/wasm/encoder.cc

Index: src/wasm/encoder.cc
diff --git a/src/wasm/encoder.cc b/src/wasm/encoder.cc
index ef0bddc836368f67f222bab432151af075f9351b..05eb0d513b07a86b8c23656ed9336a2a855ed973 100644
--- a/src/wasm/encoder.cc
+++ b/src/wasm/encoder.cc
@@ -56,7 +56,11 @@ WasmFunctionBuilder::WasmFunctionBuilder(WasmModuleBuilder* builder)
       signature_index_(0),
       exported_(0),
       body_(builder->zone()),
-      name_(builder->zone()) {}
+      name_(builder->zone()),
+      i32_temps_(builder->zone()),
+      i64_temps_(builder->zone()),
+      f32_temps_(builder->zone()),
+      f64_temps_(builder->zone()) {}
 
 void WasmFunctionBuilder::EmitVarInt(uint32_t val) {
   byte buffer[8];