[javac] some differences ecj <-> javac regarding 'recent' features

While [taking stock](https://github.com/eclipse-jdt/eclipse.jdt.core/issues/2212#issuecomment-2323293285) of `run.javac` test results regarding Java 23 I observed the following differences which might be within reach for resolution:

* PrimitiveInPatternsTestSH
* 1 javac bug see https://mail.openjdk.org/pipermail/compiler-dev/2024-September/027729.html
* MarkdownCommentTest:
* 1 error, javac not complaining about unresolvable `@see` reference
* ModuleCompilationTests
* 4 errors
* PatternMatching16Test -- is this a structural problem?
* 83 failures, obviously not suitable for running back-to-back with javac23
* 67 errors vs javac16
* RecordPatternTest 3 errors, javac-generated code throws ArithmeticException instead of expected MatchException (see comments in tests):
* testGH1977_instance_field()
* testGH1977_static_field()
* testIssue1985_2()
* SwitchExpressionsYieldTest
* currently 175 failures, many of which due to ill-configured javac invocation
* remaining: 17 failures
* SwitchPatternTest: 5 errors (some related to wrongly configured --enable-preview, others not yet analysed)
* SwitchPatternTest21: 2 errors
* testInternalDomination_this() (ecj no error, javac 2 errors)
* testNaming() // javac jdk21 allows components to be named, but they can't be referenced