riscv64: disable gtests for unsupported components.

Bug: b/271573990

Test: gtests on host:
  lunch aosp_riscv64-userdebug && m test-art-host-gtest

Test: gtests on target (on a Linux RISC-V VM):
  lunch aosp_riscv64-userdebug

  export ART_TEST_SSH_USER=ubuntu
  export ART_TEST_SSH_HOST=localhost
  export ART_TEST_SSH_PORT=10001
  export ART_TEST_ON_VM=true

  . art/tools/buildbot-utils.sh
  art/tools/buildbot-build.sh --target

  # Create, boot and configure the VM.
  art/tools/buildbot-vm.sh create
  art/tools/buildbot-vm.sh boot
  art/tools/buildbot-vm.sh setup-ssh  # password: 'ubuntu'

  art/tools/buildbot-cleanup-device.sh
  art/tools/buildbot-setup-device.sh
  art/tools/buildbot-sync.sh

  art/tools/run-gtests.sh

Change-Id: I278e3453406a91a5e9d03645cafb9a9d1f82d896
diff --git a/compiler/optimizing/loop_optimization_test.cc b/compiler/optimizing/loop_optimization_test.cc
index 7f694fb..49e3c04 100644
--- a/compiler/optimizing/loop_optimization_test.cc
+++ b/compiler/optimizing/loop_optimization_test.cc
@@ -30,6 +30,7 @@
 class LoopOptimizationTest : public OptimizingUnitTest {
  protected:
   void SetUp() override {
+    TEST_SETUP_DISABLED_FOR_RISCV64();
     OptimizingUnitTest::SetUp();
 
     graph_ = CreateGraph();
@@ -44,6 +45,7 @@
   }
 
   void TearDown() override {
+    TEST_TEARDOWN_DISABLED_FOR_RISCV64();
     codegen_.reset();
     compiler_options_.reset();
     graph_ = nullptr;
@@ -134,17 +136,20 @@
 //
 
 TEST_F(LoopOptimizationTest, NoLoops) {
+  TEST_DISABLED_FOR_RISCV64();
   PerformAnalysis();
   EXPECT_EQ("", LoopStructure());
 }
 
 TEST_F(LoopOptimizationTest, SingleLoop) {
+  TEST_DISABLED_FOR_RISCV64();
   AddLoop(entry_block_, return_block_);
   PerformAnalysis();
   EXPECT_EQ("[]", LoopStructure());
 }
 
 TEST_F(LoopOptimizationTest, LoopNest10) {
+  TEST_DISABLED_FOR_RISCV64();
   HBasicBlock* b = entry_block_;
   HBasicBlock* s = return_block_;
   for (int i = 0; i < 10; i++) {
@@ -156,6 +161,7 @@
 }
 
 TEST_F(LoopOptimizationTest, LoopSequence10) {
+  TEST_DISABLED_FOR_RISCV64();
   HBasicBlock* b = entry_block_;
   HBasicBlock* s = return_block_;
   for (int i = 0; i < 10; i++) {
@@ -167,6 +173,7 @@
 }
 
 TEST_F(LoopOptimizationTest, LoopSequenceOfNests) {
+  TEST_DISABLED_FOR_RISCV64();
   HBasicBlock* b = entry_block_;
   HBasicBlock* s = return_block_;
   for (int i = 0; i < 10; i++) {
@@ -194,6 +201,7 @@
 }
 
 TEST_F(LoopOptimizationTest, LoopNestWithSequence) {
+  TEST_DISABLED_FOR_RISCV64();
   HBasicBlock* b = entry_block_;
   HBasicBlock* s = return_block_;
   for (int i = 0; i < 10; i++) {
@@ -215,6 +223,7 @@
 //
 // This is a test for nodes.cc functionality - HGraph::SimplifyLoop.
 TEST_F(LoopOptimizationTest, SimplifyLoopReoderPredecessors) {
+  TEST_DISABLED_FOR_RISCV64();
   // Can't use AddLoop as we want special order for blocks predecessors.
   HBasicBlock* header = new (GetAllocator()) HBasicBlock(graph_);
   HBasicBlock* body = new (GetAllocator()) HBasicBlock(graph_);
@@ -260,6 +269,7 @@
 //
 // This is a test for nodes.cc functionality - HGraph::SimplifyLoop.
 TEST_F(LoopOptimizationTest, SimplifyLoopSinglePreheader) {
+  TEST_DISABLED_FOR_RISCV64();
   HBasicBlock* header = AddLoop(entry_block_, return_block_);
 
   header->InsertInstructionBefore(