ARGC exceptions when translating

We are trying to use garbage collection approach in our project to see if it helps with some of the memory issues we're facing, but we've been struggling with exceptions that arise during translation. We've built j2objc from `master-ARGC` branch according to the instructions (we've successfully did this with previous releases). The issues we're having arise when translating dependencies that we use, specifically Joda Convert (v1.8) and jtry.

```
error: internal error translating "/.../build/j2objc/java/source/org/joda/convert/AbstractTypeStringConverter.java"
com.google.devtools.j2objc.ast.TreeVisitorError: /.../build/j2objc/java/source/org/joda/convert/AbstractTypeStringConverter.java:36: NullPointerException: null
at com.google.devtools.j2objc.util.TypeUtil.asTypeElement(TypeUtil.java:238)
at com.google.devtools.j2objc.ast.TypeDeclaration.acceptInner(TypeDeclaration.java:95)
at com.google.devtools.j2objc.ast.TreeNode.accept(TreeNode.java:82)
at com.google.devtools.j2objc.ast.ChildLink.accept(ChildLink.java:76)
at com.google.devtools.j2objc.ast.ChildList.accept(ChildList.java:90)
at com.google.devtools.j2objc.ast.CompilationUnit.acceptInner(CompilationUnit.java:194)
at com.google.devtools.j2objc.ast.TreeNode.accept(TreeNode.java:82)
at com.google.devtools.j2objc.ast.UnitTreeVisitor.run(UnitTreeVisitor.java:50)
at com.google.devtools.j2objc.pipeline.TranslationProcessor.applyMutations(TranslationProcessor.java:152)
at com.google.devtools.j2objc.pipeline.TranslationProcessor.processConvertedTree(TranslationProcessor.java:107)
at com.google.devtools.j2objc.pipeline.FileProcessor.processCompiledSource(FileProcessor.java:169)
at com.google.devtools.j2objc.pipeline.FileProcessor.access$000(FileProcessor.java:43)
at com.google.devtools.j2objc.pipeline.FileProcessor$1.handleParsedUnit(FileProcessor.java:141)
at com.google.devtools.j2objc.javac.JavacParser.parseFiles(JavacParser.java:299)
at com.google.devtools.j2objc.pipeline.FileProcessor.processBatch(FileProcessor.java:146)
at com.google.devtools.j2objc.pipeline.FileProcessor.processInputs(FileProcessor.java:71)
at com.google.devtools.j2objc.pipeline.TranslationProcessor.processInputs(TranslationProcessor.java:83)
at com.google.devtools.j2objc.J2ObjC.runEx(J2ObjC.java:138)
at com.google.devtools.j2objc.J2ObjC.main(J2ObjC.java:200)
```

We have this exception for ~50 files. Stacktrace is exactly the same for all of them. We're using Java 1.8.0_221. None of these exceptions arise when translating with 2.4, 2.5 or 2.6

I'd greatly appreciate any suggestions to make this work for us 🙏