Added GN target for isac_test.

BUG=webrtc:6191
NOTRY=True
NOPRESUBMIT=True

Review-Url: https://codereview.webrtc.org/2267423002
Cr-Commit-Position: refs/heads/master@{#13884}

webrtc/modules/audio_coding/BUILD.gn

@@ -1540,6 +1540,35 @@ if (rtc_include_tests) {
     }
   }
 
+  executable("isac_test") {
+    testonly = true
+
+    sources = [
+      "codecs/isac/main/test/simpleKenny.c",
+      "codecs/isac/main/util/utility.c",
+    ]
+
+    include_dirs = [
+      "codecs/isac/main/include",
+      "codecs/isac/main/test",
+      "codecs/isac/main/util",
+    ]
+
+    deps = [
+      ":isac",
+      "../../base:rtc_base",
+      "//build/config/sanitizers:deps",
+    ]
+
+    if (is_win && is_clang) {
+      cflags = [
+        # Disable warnings failing when compiling with Clang on Windows.
+        # https://bugs.chromium.org/p/webrtc/issues/detail?id=5366
+        "-Wno-format",
+      ]
+    }
+  }
+
   executable("g711_test") {
     testonly = true