Opt hwui_unit_tests (and benchmarks) out of test runner sharding

Testing this to see if it helps weird issues seen on b/263382503. This
has been suggested to be a culprit for other very similar issues in the
past.

Docs: https://source.android.com/docs/core/tests/tradefed/testing/through-suite/android-test-tuning
Bug: 263382503
Test: presubmits
Change-Id: If54c281a5620303f1e6284a52655003a1a01147d

libs/hwui/AndroidTest.xml

@@ -21,6 +21,7 @@
         <option name="push" value="hwuimacro->/data/local/tmp/benchmarktest/hwuimacro" />
     </target_preparer>
     <option name="test-suite-tag" value="apct" />
+    <option name="not-shardable" value="true" />
     <test class="com.android.tradefed.testtype.GTest" >
         <option name="native-test-device-path" value="/data/local/tmp/nativetest" />
         <option name="module-name" value="hwui_unit_tests" />