Enable more unittests on iOS, and disable those that fail on simulator

Tests enabled:
* modules_unittests
* ortc_unittests
* rtc_media_unittests
* rtc_unittests
* video_capture_tests
* video_engine_tests

BUG=webrtc:5566,webrtc:4752,webrtc:5568,webrtc:5569

Review-Url: https://codereview.webrtc.org/2938193002
Cr-Commit-Position: refs/heads/master@{#18710}

tools_webrtc/ios/tests/common_tests.json

@@ -16,12 +16,24 @@
     {
       "app": "modules_tests"
     },
+    {
+      "app": "modules_unittests"
+    },
+    {
+      "app": "ortc_unittests"
+    },
+    {
+      "app": "rtc_media_unittests"
+    },
     {
       "app": "rtc_pc_unittests"
     },
     {
       "app": "rtc_stats_unittests"
     },
+    {
+      "app": "rtc_unittests"
+    },
     {
       "app": "system_wrappers_unittests"
     },
@@ -31,6 +43,12 @@
     {
       "app": "tools_unittests"
     },
+    {
+      "app": "video_capture_tests"
+    },
+    {
+      "app": "video_engine_tests"
+    },
     {
       "app": "voice_engine_unittests"
     },