[NFC] Precommit test for issue llvm#149512 (llvm#153541)

(cherry picked from commit 793a6b4)

Author: Ami-zhang

clang/test/CodeGen/LoongArch/targetattr-lasx.c

@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -triple loongarch64 -target-feature -lsx -emit-llvm %s -o - | FileCheck %s
+
+__attribute__((target("lasx")))
+// CHECK: #[[ATTR0:[0-9]+]] {
+void testlasx() {}
+
+// CHECK: attributes #[[ATTR0]] = { {{.*}}"target-features"="+64bit,+lasx,-lsx"{{.*}} }