Add llvm-stress binary to Bazel build configuration.

The `llvm-stress` binary is currently missing from the Bazel `BUILD` file for llvm. This patch adds it.

Reviewed By: GMNGeoffrey

Differential Revision: https://reviews.llvm.org/D107571

Author: vettoreldaniele

utils/bazel/llvm-project-overlay/llvm/BUILD.bazel

@@ -3279,6 +3279,20 @@ gentbl(
     ],
 )
 
+cc_binary(
+    name = "llvm-stress",
+    srcs = glob([
+        "tools/llvm-stress/*.cpp",
+        "tools/llvm-stress/*.h",
+    ]),
+    copts = llvm_copts,
+    stamp = 0,
+    deps = [
+        ":Core",
+        ":Support",
+    ],
+)
+
 cc_binary(
     name = "llvm-objcopy",
     srcs = glob([