a number of launcher tests fail when run with --limit-modules due to CNFE: javax.tools.ToolProvider

Affected tests:
tools/launcher/ArgFileSyntax.java
tools/launcher/ArgsEnvVar.java
tools/launcher/ArgsFileTest.java
tools/launcher/Arrrghs.java
tools/launcher/BigJar.java
tools/launcher/ChangeDataModel.java
tools/launcher/DefaultLocaleTestRun.java
tools/launcher/DiacriticTest.java
tools/launcher/ExecutionEnvironment.java
tools/launcher/I18NArgTest.java
tools/launcher/I18NJarTest.java
tools/launcher/I18NTest.java
tools/launcher/Jexec.java
tools/launcher/LauncherMessageTest.java
tools/launcher/MainClassAttributeTest.java
tools/launcher/MainClassCantBeLoadedTest.java
tools/launcher/MiscTests.java
tools/launcher/MultipleJRERemoved.java
tools/launcher/RunpathTest.java
tools/launcher/Settings.java
tools/launcher/Test7029048.java
tools/launcher/TestMainWithoutEnclosing.java
tools/launcher/TestSpecialArgs.java
tools/launcher/TooSmallStackSize.java
tools/launcher/ToolsOpts.java
tools/launcher/UnicodeTest.java
tools/launcher/UnresolvedExceptions.java
tools/launcher/VersionCheck.java