ART: Make InstructionSet an enum class and add kLast.

Adding InstructionSet::kLast shall make it easier to encode
the InstructionSet in fewer bits using BitField<>. However,
introducing `kLast` into the `art` namespace is not a good
idea, so we change the InstructionSet to an enum class.
This also uncovered a case of InstructionSet::kNone being
erroneously used instead of vixl32::Condition::None(), so
it's good to remove `kNone` from the `art` namespace.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Change-Id: I6fa6168dfba4ed6da86d021a69c80224f09997a6

1 files changed, 2 insertions, 2 deletions

diff --git a/runtime/jit/jit_code_cache.cc b/runtime/jit/jit_code_cache.cc
index 47615f56fe..e1807525ea 100644
--- a/runtime/jit/jit_code_cache.cc
+++ b/runtime/jit/jit_code_cache.cc
@@ -1223,8 +1223,8 @@ bool JitCodeCache::CheckLiveCompiledCodeHasProfilingInfo() {
 }
 
 OatQuickMethodHeader* JitCodeCache::LookupMethodHeader(uintptr_t pc, ArtMethod* method) {
-  static_assert(kRuntimeISA != kThumb2, "kThumb2 cannot be a runtime ISA");
-  if (kRuntimeISA == kArm) {
+  static_assert(kRuntimeISA != InstructionSet::kThumb2, "kThumb2 cannot be a runtime ISA");
+  if (kRuntimeISA == InstructionSet::kArm) {
     // On Thumb-2, the pc is offset by one.
     --pc;
   }