A64: Initialize CPURegisters before we use them in MacroAssembler::PrintfNoPreserve

src/a64/macro-assembler-a64.cc

Index: src/a64/macro-assembler-a64.cc
diff --git a/src/a64/macro-assembler-a64.cc b/src/a64/macro-assembler-a64.cc
index 7a245ad65ac776592afb2ad7e7e4a33ec65fd6f0..3d2d24e9e9277c2be15b3099de9e7cdca94e53df 100644
--- a/src/a64/macro-assembler-a64.cc
+++ b/src/a64/macro-assembler-a64.cc
@@ -4542,7 +4542,7 @@ void MacroAssembler::PrintfNoPreserve(const char * format,
   CPURegister args[kMaxArgCount] = {arg0, arg1, arg2, arg3};
 
   // The PCS registers where the arguments need to end up.
-  CPURegister pcs[kMaxArgCount];
+  CPURegister pcs[kMaxArgCount] = {NoCPUReg, NoCPUReg, NoCPUReg, NoCPUReg};
 
   // Promote FP arguments to doubles, and integer arguments to X registers.
   // Note that FP and integer arguments cannot be mixed, but we'll check