Remove hard-wired basenames for the test setup and the coverage collection script.

Accomplished by creating an explicit attribute for both of them on test actions.

RELNOTES: None.
PiperOrigin-RevId: 185132460
diff --git a/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java b/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java
index a6fbd41..b5748ee 100644
--- a/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java
+++ b/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java
@@ -53,15 +53,12 @@
 import java.util.Map;
 
 /** Runs TestRunnerAction actions. */
+// TODO(bazel-team): add tests for this strategy.
 @ExecutionStrategy(
   contextType = TestActionContext.class,
   name = {"standalone"}
 )
 public class StandaloneTestStrategy extends TestStrategy {
-  // TODO(bazel-team) - add tests for this strategy.
-  public static final String COLLECT_COVERAGE =
-      "external/bazel_tools/tools/test/collect_coverage.sh";
-
   private static final ImmutableMap<String, String> ENV_VARS =
       ImmutableMap.<String, String>builder()
           .put("TZ", "UTC")
@@ -121,7 +118,7 @@
     Spawn spawn =
         new SimpleSpawn(
             action,
-            getArgs(COLLECT_COVERAGE, action),
+            getArgs(action),
             ImmutableMap.copyOf(env),
             executionInfo.build(),
             new RunfilesSupplierImpl(