Drop "manylinux_2_39_riscv64" from tests

manylinux_X_Y_* is covered by manylinux_11_12_riscv64 pattern
where _11_ and _12_ will be replaced.

Author: kxxt

tests/pypi/whl_target_platforms/whl_target_platforms_tests.bzl

@@ -104,7 +104,6 @@ def _can_parse_existing_tags(env):
         "manylinux2014_ppc64le": 1,
         "manylinux2014_s390x": 1,
         "manylinux2014_x86_64": 1,
-        "manylinux_2_39_riscv64": 1,
         "manylinux_11_12_aarch64": 1,
         "manylinux_11_12_armv7l": 1,
         "manylinux_11_12_i686": 1,