The LocustParser was added in 3.18, but it's actually not usable from within Jenkins because a branch for the LocustParser is missing from the ParserFactory.

When trying to load a locust report using `perfReport`, I get the following exception:

java.lang.IllegalArgumentException: Unknown parser type: LocustParser at hudson.plugins.performance.parsers.ParserFactory.getParser(ParserFactory.java:156) at hudson.plugins.performance.parsers.ParserFactory.getParserUsingAntPatternRelativePath(ParserFactory.java:76) at hudson.plugins.performance.parsers.ParserFactory.getParserWithRelativePath(ParserFactory.java:47) at hudson.plugins.performance.parsers.ParserFactory.getParser(ParserFactory.java:43) at hudson.plugins.performance.PerformancePublisher.getParsers(PerformancePublisher.java:339) at hudson.plugins.performance.PerformancePublisher.perform(PerformancePublisher.java:390) at jenkins.tasks.SimpleBuildStep.perform(SimpleBuildStep.java:123) at org.jenkinsci.plugins.workflow.steps.CoreStep$Execution.run(CoreStep.java:99) at org.jenkinsci.plugins.workflow.steps.CoreStep$Execution.run(CoreStep.java:69) at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution.lambda$start$0(SynchronousNonBlockingStepExecution.java:47) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)

When trying to use `performanceReport` instead with an explicit class name, I got this exception instead:
org.kohsuke.stapler.NoStaplerConstructorException: There's no @DataBoundConstructor on any constructor of class hudson.plugins.performance.parsers.LocustParser at org.kohsuke.stapler.ClassDescriptor.loadConstructorParamNames(ClassDescriptor.java:265) at org.jenkinsci.plugins.structs.describable.DescribableModel.<init>(DescribableModel.java:153) at org.jenkinsci.plugins.structs.describable.DescribableModel.coerce(DescribableModel.java:474) at org.jenkinsci.plugins.structs.describable.DescribableModel.coerceList(DescribableModel.java:585) at org.jenkinsci.plugins.structs.describable.DescribableModel.coerce(DescribableModel.java:458) at org.jenkinsci.plugins.structs.describable.DescribableModel.injectSetters(DescribableModel.java:429) at org.jenkinsci.plugins.structs.describable.DescribableModel.instantiate(DescribableModel.java:331)