[fuchsia-test-runner] Explicitly target fuchsia-emulator

By explicitly specifying the fuchsia-emulator target, locally running fuchsia-test-runner.py will not fail when there are other targets available.

Author: c6c7

src/ci/docker/scripts/fuchsia-test-runner.py

@@ -620,6 +620,8 @@ def start(self):
         check_call_with_logging(
             [
                 ffx_path,
+                "-t",
+                "fuchsia-emulator",
                 "target",
                 "repository",
                 "register",
@@ -882,6 +884,8 @@ def run(self, args):
         check_call_with_logging(
             [
                 self.tool_path("ffx"),
+                "-t",
+                "fuchsia-emulator",
                 "test",
                 "run",
                 f"fuchsia-pkg://{self.TEST_REPO_NAME}/{package_name}#meta/{package_name}.cm",
@@ -1019,6 +1023,8 @@ def cleanup(self):
     def debug(self, args):
         command = [
             self.tool_path("ffx"),
+            "-t",
+            "fuchsia-emulator",
             "debug",
             "connect",
             "--",
@@ -1116,6 +1122,8 @@ def syslog(self, args):
         subprocess.run(
             [
                 self.tool_path("ffx"),
+                "-t",
+                "fuchsia-emulator",
                 "log",
                 "--since",
                 "now",