libmanage.py: remove --no-ada-api

The actual feature behind this flag has been removed for a long time
(the generic introspection API, always generated, depends on the public
Ada API), so remove the last bits.

Author: pmderodat

langkit/libmanage.py

@@ -372,11 +372,6 @@ def add_common_args(subparser: argparse.ArgumentParser) -> None:
             '--trace', '-t', action='append', default=[],
             help='Activate given debug trace.'
         )
-        subparser.add_argument(
-            '--no-ada-api', action='store_true',
-            help='Do not generate units to provide an Ada API, and disable the'
-                 ' generation of mains.'
-        )
 
         # Don't enable this by default so that errors will not make automated
         # tasks hang.

testsuite/python_support/utils.py

@@ -325,12 +325,6 @@ def manage_run(generate_only, types_from_lkt, additional_args):
         if full_error_traces:
             argv.append("--full-error-traces")
 
-        # Generate the public Ada API only when necessary (i.e. if we have
-        # mains that do use this API). This reduces the time it takes to run
-        # tests.
-        if not mains and not ada_main:
-            argv.append('--no-ada-api')
-
         # If there is a Java main, enable the Java bindings building
         if java_main is not None or ni_main is not None:
             argv.append('--enable-java')