Expose some APIs as test APIs to facilitate CTS

Test: added new cts tests
Bug: 123896388
Change-Id: I742f23be57e731307338591d816f7888e198b333
diff --git a/telecomm/java/android/telecom/Conference.java b/telecomm/java/android/telecom/Conference.java
index 7d1f8ce..6382acf 100644
--- a/telecomm/java/android/telecom/Conference.java
+++ b/telecomm/java/android/telecom/Conference.java
@@ -19,6 +19,7 @@
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.SystemApi;
+import android.annotation.TestApi;
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.SystemClock;
@@ -571,6 +572,7 @@
      * @return The primary connection.
      * @hide
      */
+    @TestApi
     @SystemApi
     public Connection getPrimaryConnection() {
         if (mUnmodifiableChildConnections == null || mUnmodifiableChildConnections.isEmpty()) {
diff --git a/telecomm/java/android/telecom/TelecomManager.java b/telecomm/java/android/telecom/TelecomManager.java
index 12a5344..b0993b7 100644
--- a/telecomm/java/android/telecom/TelecomManager.java
+++ b/telecomm/java/android/telecom/TelecomManager.java
@@ -22,6 +22,7 @@
 import android.annotation.SuppressLint;
 import android.annotation.SystemApi;
 import android.annotation.SystemService;
+import android.annotation.TestApi;
 import android.annotation.UnsupportedAppUsage;
 import android.app.role.RoleManagerCallback;
 import android.content.ComponentName;
@@ -552,6 +553,7 @@
      *
      * @hide
      */
+    @TestApi
     @SystemApi
     public static final int TTY_MODE_OFF = 0;
 
@@ -561,6 +563,7 @@
      *
      * @hide
      */
+    @TestApi
     @SystemApi
     public static final int TTY_MODE_FULL = 1;
 
@@ -571,6 +574,7 @@
      *
      * @hide
      */
+    @TestApi
     @SystemApi
     public static final int TTY_MODE_HCO = 2;
 
@@ -581,6 +585,7 @@
      *
      * @hide
      */
+    @TestApi
     @SystemApi
     public static final int TTY_MODE_VCO = 3;
 
@@ -819,6 +824,7 @@
      * @hide
      */
     @RequiresPermission(android.Manifest.permission.MODIFY_PHONE_STATE)
+    @TestApi
     @SystemApi
     public void setUserSelectedOutgoingPhoneAccount(PhoneAccountHandle accountHandle) {
         try {
@@ -1508,6 +1514,7 @@
      * @hide
      */
     @SystemApi
+    @TestApi
     @RequiresPermission(android.Manifest.permission.READ_PRIVILEGED_PHONE_STATE)
     public @TtyMode int getCurrentTtyMode() {
         try {
@@ -1956,6 +1963,7 @@
      * @hide
      */
     @SystemApi
+    @TestApi
     @RequiresPermission(android.Manifest.permission.MODIFY_PHONE_STATE)
     public boolean isInEmergencyCall() {
         try {