Fix SKIPIF section

Author: carusogabriel

README.TESTING

@@ -61,7 +61,7 @@ test scripts by extracting all directories named "tests"
 from the source root and any subdirectories below. If there are files,
 which have a "phpt" extension, "run-tests.php" looks at the sections
 in these files, determines whether it should run it, by evaluating
-the 'SKIP' section. If the test is eligible for execution, the 'FILE'
+the 'SKIPIF' section. If the test is eligible for execution, the 'FILE'
 section is extracted into a ".php" file (with the same name besides
 the extension) and gets executed.
 When an argument is given or TESTS environment variable is set, the