Reduce dartfuzz's build set.

dartfuzz has been taking ~35 min to finish the build and upload steps even with 100% RBE cache hit rate, causing it to fail to finish before the first wave of nightly builders trigger.

Change-Id: I932facd77bc08f4d7236ae8c760013406a69fb0e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/507267
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>

runtime/tools/dartfuzz/dartfuzz_test.dart

@@ -116,7 +116,7 @@ class TestRunnerJIT implements TestRunner {
     List<String> extraFlags,
   ) {
     description = '$prefix-$tag';
-    dart = '$top/out/$tag/dart';
+    dart = '$top/out/$tag/dartvm';
     cmd = [dart, ...extraFlags, '--old_gen_heap_size=$dartHeapSize', fileName];
   }
 

runtime/tools/dartfuzz/flag_fuzzer.dart

@@ -176,7 +176,7 @@ Future<void> test(
     // JIT
     commands = [
       [
-        "$buildDir/dart",
+        "$buildDir/dartvm",
         ...someJitRuntimeFlags(),
         dartScript,
         ...dartArguments,
@@ -191,7 +191,7 @@ Future<void> test(
     // AOT
     commands = [
       [
-        "out/ReleaseX64/dart",
+        "out/ReleaseX64/dartvm",
         "pkg/vm/bin/gen_kernel.dart",
         "--platform=$buildDir/vm_platform.dill",
         "--aot",
@@ -284,7 +284,7 @@ Future<void> flagFuzz(
 
   await Directory("out/dartfuzz").create();
 
-  var executable = "out/ReleaseX64/dart";
+  var executable = "out/ReleaseX64/dartvm";
   var arguments = createDartCommand("out/dartfuzz/expected.$extension");
   var processResult = await Process.run(executable, arguments);
   if (processResult.exitCode != 0) {