sci-electronics/verilator: add 5.048-r2, drop 5.048-r1

- test_regress/driver.py imports the third-party 'distro' module,
  which was not declared in BDEPEND, so FEATURES=test crashed with
  ModuleNotFoundError before any test could run.
- Add dev-python/distro under the test? block.

Closes: https://bugs.gentoo.org/975581
Signed-off-by: Huang Rui <vowstar@gmail.com>

sci-electronics/verilator/verilator-5.048-r2.ebuild

@@ -43,6 +43,7 @@ BDEPEND="
 	test? (
 		dev-build/cmake
 		dev-debug/gdb
+		$(python_gen_cond_dep 'dev-python/distro[${PYTHON_USEDEP}]')
 	)
 "