Move definition of NegateConditon from assembler*-inl.h files to...

src/x64/assembler-x64.h

Index: src/x64/assembler-x64.h
===================================================================
--- src/x64/assembler-x64.h	(revision 4878)
+++ src/x64/assembler-x64.h	(working copy)
@@ -215,8 +215,11 @@
 // Negation of the default no_condition (-1) results in a non-default
 // no_condition value (-2). As long as tests for no_condition check
 // for condition < 0, this will work as expected.
-inline Condition NegateCondition(Condition cc);
+inline Condition NegateCondition(Condition cc) {
+  return static_cast<Condition>(cc ^ 1);
+}
 
+
 // Corresponds to transposing the operands of a comparison.
 inline Condition ReverseCondition(Condition cc) {
   switch (cc) {
@@ -241,6 +244,7 @@
   };
 }
 
+
 enum Hint {
   no_hint = 0,
   not_taken = 0x2e,