If a rule contains all files in the directory, name it after the directory and use a `glob`

[cgrushko]

That is, instead of

java_test(
    name = "JavaBuildRule_0a5e5865c4cb7b46",
    srcs = [
        "ParallelCollectTest.java",
        "ParallelDoOnNextTryTest.java",
        "ParallelFilterTest.java",
        "ParallelFilterTryTest.java",
        "ParallelFlowableTest.java",
        "ParallelFromPublisherTest.java",
        "ParallelInvalid.java",
        "ParallelJoinTest.java",
        "ParallelMapTest.java",
        "ParallelMapTryTest.java",
        "ParallelPeekTest.java",
        "ParallelReduceFullTest.java",
        "ParallelReduceTest.java",
        "ParallelRunOnTest.java",
        "ParallelSortedJoinTest.java",
    ],
    deps = [
        "//src/main/java/io/reactivex:JavaBuildRule_702766528d9e97ce",
        "//src/test/java/io/reactivex/exceptions:JavaBuildRule_4ef8b1dd986b3f53",
    ],
)

we should have

java_test(
    name = "parallel",
    srcs = glob(["*.java"]),
    deps = [
        "//src/main/java/io/reactivex:JavaBuildRule_702766528d9e97ce",
        "//src/test/java/io/reactivex/exceptions:JavaBuildRule_4ef8b1dd986b3f53",
    ],
)