Revert "Arm64: Ensure that csp is always aligned to 16 byte values even if jssp is not." and "Arm64…

src/arm64/cpu-arm64.h

Index: src/arm64/cpu-arm64.h
diff --git a/src/arm64/cpu-arm64.h b/src/arm64/cpu-arm64.h
index 11e629c636d5da9e19c2844acc67db0761090df2..0b7a7d7f1feab31931c1dd3207350c607b3a57f7 100644
--- a/src/arm64/cpu-arm64.h
+++ b/src/arm64/cpu-arm64.h
@@ -24,9 +24,11 @@ class CpuFeatures : public AllStatic {
   // Check whether a feature is supported by the target CPU.
   static bool IsSupported(CpuFeature f) {
     ASSERT(initialized_);
-    return Check(f, supported_);
+    // There are no optional features for ARM64.
+    return false;
   };
 
+  // There are no optional features for ARM64.
   static bool IsSafeForSnapshot(Isolate* isolate, CpuFeature f) {
     return IsSupported(f);
   }
@@ -38,13 +40,16 @@ class CpuFeatures : public AllStatic {
   static unsigned supported_;
 
   static bool VerifyCrossCompiling() {
-    return cross_compile_ == 0;
+    // There are no optional features for ARM64.
+    ASSERT(cross_compile_ == 0);
+    return true;
   }
 
   static bool VerifyCrossCompiling(CpuFeature f) {
-    unsigned mask = flag2set(f);
-    return cross_compile_ == 0 ||
-           (cross_compile_ & mask) == mask;
+    // There are no optional features for ARM64.
+    USE(f);
+    ASSERT(cross_compile_ == 0);
+    return true;
   }
 
   static bool SupportsCrankshaft() { return true; }
@@ -54,17 +59,9 @@ class CpuFeatures : public AllStatic {
   static bool initialized_;
 #endif
 
-  static unsigned found_by_runtime_probing_only_;
+  // This isn't used (and is always 0), but it is required by V8.
   static unsigned cross_compile_;
 
-  static bool Check(CpuFeature f, unsigned set) {
-    return (set & flag2set(f)) != 0;
-  }
-
-  static unsigned flag2set(CpuFeature f) {
-    return 1u << f;
-  }
-
   friend class PlatformFeatureScope;
   DISALLOW_COPY_AND_ASSIGN(CpuFeatures);
 };