[JVM IR] Stabilize accesor names in IR Backend

- introduce a scoped counter instead of a global one for name
  generation for accessors. Naive solution not working.

- Introduced hardcoded "jd" suffix for accessors on interfaces, under
  the assumption that the only such accessors are due to JvmDefault
  and their bridges from `$DefaultImpls`. Removed all associated
  templated tests, so the old and IR backend correspond on this matter
  again.

- Respecialized writeFlags from regexps to string-equality: we are
  going for exact matches now!

- Fixed package calculation in `IrUtils.kt`.

- Accessors for static members must be due to accessing super
  classes. Actual super-qualified calls are naturally also accessing
  super classes. Hence the `$s+{hashcode(superClassName)}`
  suffix. Added test to affirm this naming scheme.

- Field getters/setters for static fields must be companion accessors,
  otherwise just labelled as accessors. They are also tagged with `s`
  suffix when accessing static fields.

- For naming of accessors to coincide with the old backend, field
  renaming to avoid JVM signature clashes must be done _after_
  generation of accessors for those fields.

compiler/testData/codegen/bytecodeText/companion/kt14258_2.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 // Checks that methods 'access$getMy$p' and 'getMy' are not generated and
 // that backed field 'my' is accessed through 'access$getMy$cp'