remove all occurences of "__multicall__" on hook impls in pytest/*.

also simplify pytest_runtest_markereport hook in _pytest/skipping.py
while touching the code anyway.

testing/python/collect.py

@@ -525,12 +525,15 @@ class TestConftestCustomization:
     def test_customized_pymakeitem(self, testdir):
         b = testdir.mkdir("a").mkdir("b")
         b.join("conftest.py").write(py.code.Source("""
-            def pytest_pycollect_makeitem(__multicall__):
-                result = __multicall__.execute()
-                if result:
-                    for func in result:
-                        func._some123 = "world"
-                return result
+            import pytest
+            @pytest.mark.hookwrapper
+            def pytest_pycollect_makeitem():
+                outcome = yield
+                if outcome.excinfo is None:
+                    result = outcome.result
+                    if result:
+                        for func in result:
+                            func._some123 = "world"
         """))
         b.join("test_module.py").write(py.code.Source("""
             import pytest

testing/test_mark.py

@@ -509,11 +509,13 @@ class TestKeywordSelection:
                     pass
         """)
         testdir.makepyfile(conftest="""
-            def pytest_pycollect_makeitem(__multicall__, name):
+            import pytest
+            @pytest.mark.hookwrapper
+            def pytest_pycollect_makeitem(name):
+                outcome = yield
                 if name == "TestClass":
-                    item = __multicall__.execute()
+                    item = outcome.get_result()
                     item.extra_keyword_matches.add("xxx")
-                    return item
         """)
         reprec = testdir.inline_run(p.dirpath(), '-s', '-k', keyword)
         py.builtin.print_("keyword", repr(keyword))