[test] Disable the -Wself-move warning that triggers on exactly what is being tested (NFC)

/Users/jiefu/llvm-project/llvm/unittests/Option/OptionParsingTest.cpp:251:6: error: explicitly moving variable of type 'InputArgList' to itself [-Werror,-Wself-move]
  AL = std::move(AL);
  ~~ ^           ~~
1 error generated.

Author: DamonFool

llvm/unittests/Option/OptionParsingTest.cpp

@@ -238,6 +238,12 @@ TYPED_TEST(OptTableTest, IgnoreCase) {
   EXPECT_TRUE(AL.hasArg(OPT_B));
 }
 
+#if defined(__clang__)
+// Disable the warning that triggers on exactly what is being tested.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wself-move"
+#endif
+
 TYPED_TEST(OptTableTest, InputArgListSelfAssign) {
   TypeParam T;
   unsigned MAI, MAC;
@@ -255,6 +261,10 @@ TYPED_TEST(OptTableTest, InputArgListSelfAssign) {
   EXPECT_FALSE(AL.hasArg(OPT_SLASH_C));
 }
 
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+
 TYPED_TEST(OptTableTest, DoNotIgnoreCase) {
   TypeParam T;
   unsigned MAI, MAC;