Temporarily remove chrome_app_unittests from the Dr. Memory builder

testing/buildbot/chromium.full.json

 {
   "Chromium Windows Builder (DrMemory x64)": {
     "additional_compile_targets": [
       "accessibility_unittests",
       "angle_unittests",
       "aura_unittests",
       "base_unittests",
       "blink_heap_unittests",
       "blink_platform_unittests",
       "cacheinvalidation_unittests",
@@ skipping 78 matching lines @@
       "display_unittests",
       "extensions_unittests",
       "events_unittests",
       "gin_unittests",
       "google_apis_unittests",
       "gfx_unittests",
       "installer_util_unittests",
       "install_static_unittests",
       "keyboard_unittests",
       "unit_tests",
-      "chrome_app_unittests",
       "libaddressinput_unittests",
       "libphonenumber_unittests",
       "content_browsertests",
       "browser_tests"
     ]
   },
   "Linux ChromeOS MSan Tests": {
     "gtest_tests": [
       {
         "swarming": {
@@ skipping 1918 matching lines @@
       },
       {
         "test": "unit_tests"
       },
       {
         "test": "url_unittests"
       }
     ]
   }
 }