Revert "Build ext_zend_compat extensions by default"

This reverts commit 8bf8e13796.

Not behaving as it's supposed to.  Revert until I can figure that out.

CMake/ExtZendCompat.cmake

@@ -1,4 +1,4 @@
-option(ENABLE_ZEND_COMPAT "Enable Zend source compatibility (beta)" ON)
+option(ENABLE_ZEND_COMPAT "Enable Zend source compatibility (beta)" OFF)
 
 set(ZEND_COMPAT_PROJECTS)
 set(ZEND_COMPAT_BUILD_DIRS)