Switch profiling from HPROF to Java Flight Recorder.

After the switch to Java 11 (#343), the JVM TI hprof Agent (introduced in e144936) is no longer available (removed in JDK 9, see https://bugs.openjdk.org/browse/JDK-8046661).

Use the `jfr` command-line tool or JDK Mission Control (https://jdk.java.net/jmc/) to analyze the recording file.

.gitignore

@@ -6,7 +6,7 @@ out/
 node_modules/
 xtext-server/
 package-lock.json
-*.hprof.txt
+*.jfr
 *.vsix
 /metafix/src/test/resources/org/metafacture/metafix/integration/**/*.diff
 /metafix/src/test/resources/org/metafacture/metafix/integration/**/*.err

build.gradle

@@ -8,7 +8,7 @@ plugins {
 //  excludes = [
 //    '**/*.diff',
 //    '**/*.err',
-//    '**/*.hprof.txt',
+//    '**/*.jfr',
 //    '**/*.out',
 //    '**/*.vsix',
 //    '**/.*',

metafix-runner/build.gradle

@@ -42,8 +42,10 @@ application {
   if (project.hasProperty('profile')) {
     def file = project.getProperty('profile') ?: project.name
     def depth = project.hasProperty('profile.depth') ? project.getProperty('profile.depth') : 8
-    def cutoff = project.hasProperty('profile.cutoff') ? project.getProperty('profile.cutoff') : 0.001
 
-    applicationDefaultJvmArgs = ["-agentlib:hprof=heap=sites,cpu=samples,depth=${depth},cutoff=${cutoff},file=${file}.hprof.txt"]
+    applicationDefaultJvmArgs = [
+      "-XX:FlightRecorderOptions=stackdepth=${depth}",
+      "-XX:StartFlightRecording=dumponexit=true,filename=${file}.jfr,settings=profile"
+    ]
   }
 }