Makes scalatest available in IntelliJ (#4032)

The target override for scalatest was pointing to a meta package that
was empty itself and reexported scalactic and scalatest. It seems this
confused the IntelliJ plugin. This instead introduces dedicated
overrides for scalactic and scalatest.

CHANGELOG_BEGIN
CHANGELOG_END

Co-authored-by: Andreas Herrmann <andreash87@gmx.ch>

bazel-java-deps.bzl

@@ -126,7 +126,8 @@ def install_java_deps():
             "org.scalameta:paradise_2.12.6:3.0.0-M11",
             "org.scalameta:scalameta_2.12:1.8.0",
             "org.scala-sbt:sbt:1.1.4",
-            "org.scalatest:scalatest_2.12:3.0.8",
+            "org.scalactic:scalactic_2.12:3.0.5",
+            "org.scalatest:scalatest_2.12:3.0.5",
             "org.scalaz:scalaz-concurrent_2.12:7.2.24",
             "org.scalaz:scalaz-core_2.12:7.2.24",
             "org.scalaz:scalaz-scalacheck-binding_2.12:7.2.24-scalacheck-1.14",
@@ -156,7 +157,8 @@ def install_java_deps():
             "org.scala-lang:scala-reflect": "@io_bazel_rules_scala_scala_reflect//:io_bazel_rules_scala_scala_reflect",
             "org.scala-lang.modules:scala-parser-combinators": "@io_bazel_rules_scala_scala_parser_combinators//:io_bazel_rules_scala_scala_parser_combinators",
             "org.scala-tools.testing:test-interface": "//:org_scala_sbt_test_interface",
-            "org.scalatest:scalatest_2.12": "@io_bazel_rules_scala//scala/scalatest:scalatest",
+            "org.scalactic:scalactic_2.12": "@io_bazel_rules_scala_scalactic//:io_bazel_rules_scala_scalactic",
+            "org.scalatest:scalatest_2.12": "@io_bazel_rules_scala_scalatest//:io_bazel_rules_scala_scalatest",
         },
         repositories = [
             "https://repo1.maven.org/maven2",