SI-3809 Avoid cycles during classfile parsing

[retronym]

Manually tested with:

scalaHome := Some(file("/code/scala/build/pack"))
libraryDependencies += "com.datastax.cassandra" % "dse-driver" % "1.0.0"

class Test {
  new com.datastax.driver.dse.DseCluster.Builder()
}

I was also able to compile pos/cycle{-jsoup,} without the experimental
-Ybreak-cycles. I've removed the entire -Ybreak-cycles option and
supporting code in favour of the approach in this patch.

What's changed? I've used lazy types for methods infos, which is analagous
to what we do in Unpickler for scala originated types.

[retronym]

#
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 123207680 bytes for committing reserved memory.
# Possible reasons:
#   The system is out of physical RAM or swap space
#   In 32 bit mode, the process size limit was hit
# Possible solutions:

[retronym]

/rebuild

[retronym]

I've realized that the addition of laziness here will increase the footprint: the ConstantPool, which we access in the type completer, references $outer.in.buf, the entire contents of the class file.

I've just pushed a WIP commit to might alleviate this problem.

[Swoorup]

This is also occuring on dotty. scala/scala3#9492
Any ideas how to port the fix over? @retronym