Add support for computing iOS code coverage

Also disable failing PosixSignalDeliveryTest* tests for iOS

Bug: chromium:844647
Change-Id: I64bb233bef2f06f6778f2d475b6d3ad685fb9143
Reviewed-on: https://webrtc-review.googlesource.com/c/105641
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Reviewed-by: Peter Hanspers <peterhanspers@webrtc.org>
Reviewed-by: Artem Titarenko <artit@webrtc.org>
Commit-Queue: Artem Titarenko <artit@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25524}
diff --git a/examples/BUILD.gn b/examples/BUILD.gn
index cd931b4..d136e96 100644
--- a/examples/BUILD.gn
+++ b/examples/BUILD.gn
@@ -648,12 +648,13 @@
       rtc_ios_xctest_test("apprtcmobile_tests") {
         info_plist = "objc/AppRTCMobile/ios/Info.plist"
         sources = [
-          "objc/AppRTCMobile/ios/main.m",
+          "objc/AppRTCMobile/tests/main.mm",
         ]
         deps = [
           ":AppRTCMobile_lib",
           ":apprtcmobile_test_sources",
           "../sdk:framework_objc",
+          "//test:test_support",
         ]
         ldflags = [ "-all_load" ]
       }