Flip --enable_bzlmod to true

Bazel tests status:

- Bzlmod disabled:

  - AnalysisTestCase: to be migrated
  - ConfigurationTestCase: to be migrated
  - ConfigCommandTest: to be migrated, probably blocked by a bug

- Bzlmod enabled:

  - BuildViewTestCase: migrated at https://github.com/bazelbuild/bazel/commit/d51144c811bc4360aad812deae557e7c7fc32fc2
  - Java integration tests migrated at https://github.com/bazelbuild/bazel/commit/8d0471137361405d4903a9c24122b3cf327111b2
  - Shell integration tests migrated at https://github.com/bazelbuild/bazel/commit/175a18dc9f58ba40e287336e06a26617a0becd0a (Bzlmod disabled in some tests)
  - Python integration tests migrated at https://github.com/bazelbuild/bazel/commit/50c8375982085d9cf80650a62ac7065ba5f46259 (Bzlmod disabled in some tests)
  - BuildIntegrationTestCase: migrated in this change
  - Other Java unit tests migrated in this change

Issues identified:

- cc_shared_library doesn't work well with Bzlmod: https://github.com/bazelbuild/bazel/issues/19822
- `bazel config` doesn't work well with Bzlmod: https://github.com/bazelbuild/bazel/issues/19823

Fixes https://github.com/bazelbuild/bazel/issues/18958

Tracking migration of remaining test cases in https://github.com/bazelbuild/bazel/issues/19824

RELNOTES[INC]: Bzlmod is enabled by default, please consider migrating your external dependencies from WORKSPACE to MODULE.bazel. Find more details at https://github.com/bazelbuild/bazel/issues/18958

PiperOrigin-RevId: 573827480
Change-Id: I097b4bd7caafc996b034284ee688b8f3d2bca1f7
diff --git a/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java b/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java
index fb71902..118086d 100644
--- a/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java
+++ b/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java
@@ -55,7 +55,12 @@
   /**
    * Default workspace name.
    */
-  public static final String WORKSPACE_NAME = "__main__";
+  public static final String WORKSPACE_NAME = "_main";
+
+  /**
+   * Legacy default workspace name.
+   */
+  public static final String LEGACY_WORKSPACE_NAME = "__main__";
 
   /**
    * Name of a class with an INSTANCE field of type AnalysisMock to be used for analysis tests.