Code refactoring for end2end tests.

This change:
1) uses the new style ANGLE_SKIP_TEST_IF to skip tests.
2) replaces compile-time definition for OSX to skip tests by run-time
function IsOSX() to skip tests, in order to align with ANGLE_SKIP_TEST_IF.
3) fixes a couple of typos.

BUG=angleproject:2005

Change-Id: I5af77d82257536b9eb79e26afa502f5b91ff6d31
Reviewed-on: https://chromium-review.googlesource.com/915861
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/tests/gl_tests/MultiviewDrawTest.cpp b/src/tests/gl_tests/MultiviewDrawTest.cpp
index 58d50ea..0ed643b 100644
--- a/src/tests/gl_tests/MultiviewDrawTest.cpp
+++ b/src/tests/gl_tests/MultiviewDrawTest.cpp
@@ -762,17 +762,9 @@
 // 2) does not generate any error if the number of views in the draw framebuffer is 1.
 TEST_P(MultiviewDrawValidationTest, ActiveTimeElapsedQuery)
 {
-    if (!requestMultiviewExtension())
-    {
-        return;
-    }
+    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());
 
-    if (!extensionEnabled("GL_EXT_disjoint_timer_query"))
-    {
-        std::cout << "Test skipped because GL_EXT_disjoint_timer_query is not available."
-                  << std::endl;
-        return;
-    }
+    ANGLE_SKIP_TEST_IF(!extensionEnabled("GL_EXT_disjoint_timer_query"));
 
     const GLint viewportOffsets[4] = {0, 0, 2, 0};
     const std::string &vsSource =