Fix 'Run-As' CTS test in N

Change-Id: Ie28d3353ae5f844a7fae3b29522b2c548c89ce4c
diff --git a/hostsidetests/cpptools/src/com/android/cts/cpptools/RunAsHostTest.java b/hostsidetests/cpptools/src/com/android/cts/cpptools/RunAsHostTest.java
index ae472de..231ca83 100644
--- a/hostsidetests/cpptools/src/com/android/cts/cpptools/RunAsHostTest.java
+++ b/hostsidetests/cpptools/src/com/android/cts/cpptools/RunAsHostTest.java
@@ -35,7 +35,7 @@
         String runAsResult = getDevice().executeShellCommand("run-as android.cpptools.app id -u");
         assertNotNull("adb shell command failed", runAsResult);
         runAsResult = runAsResult.trim();
-        Matcher appIdMatcher = Pattern.compile("^uid=([0-9]+).*$").matcher(runAsResult);
+        Matcher appIdMatcher = Pattern.compile("^([0-9]+)$").matcher(runAsResult);
         assertTrue("unexpected result returned by adb shell command: \"" + runAsResult + "\"",
                    appIdMatcher.matches());
         String appIdString = appIdMatcher.group(1);
diff --git a/tools/cts-tradefed/res/config/cts-known-failures.xml b/tools/cts-tradefed/res/config/cts-known-failures.xml
index 5ba1028..9c5bd1c 100644
--- a/tools/cts-tradefed/res/config/cts-known-failures.xml
+++ b/tools/cts-tradefed/res/config/cts-known-failures.xml
@@ -71,9 +71,6 @@
 
     <option name="compatibility:exclude-filter" value="CtsCarTestCases" />
 
-    <!-- b/27578806 -->
-    <option name="compatibility:exclude-filter" value="CtsCppToolsTestCases com.android.cts.cpptools.RunAsHostTest#testRunAs" />
-
     <!-- b/23776893 -->
     <option name="compatibility:exclude-filter" value="CtsDumpsysHostTestCases android.dumpsys.cts.DumpsysHostTest#testBatterystatsOutput" />
     <option name="compatibility:exclude-filter" value="CtsDumpsysHostTestCases android.dumpsys.cts.DumpsysHostTest#testGfxinfoFramestats" />