ARM: Avoid VMSR instruction when converting to clamped uint8

src/arm/constants-arm.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 186 matching lines @@
   I   = 1 << 25,  // Immediate shifter operand (or not).
 
   B4  = 1 << 4,
   B5  = 1 << 5,
   B6  = 1 << 6,
   B7  = 1 << 7,
   B8  = 1 << 8,
   B9  = 1 << 9,
   B12 = 1 << 12,
   B16 = 1 << 16,
+  B17 = 1 << 17,
   B18 = 1 << 18,
   B19 = 1 << 19,
   B20 = 1 << 20,
   B21 = 1 << 21,
   B22 = 1 << 22,
   B23 = 1 << 23,
   B24 = 1 << 24,
   B25 = 1 << 25,
   B26 = 1 << 26,
   B27 = 1 << 27,
@@ skipping 547 matching lines @@
   static int Number(const char* name, bool* is_double);
 
  private:
   static const char* names_[kNumVFPRegisters];
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_CONSTANTS_ARM_H_