Copy jet.modules.* to kotlin.modules.*

The next step will be to use the new "kotlin.modules" package and drop the old
"jet" one
Don't check equals, hashCode, toString in LoadBuiltinsTest

Otherwise there'll be too many fake overrides when these methods will appear in
Any
Check if the class is special by FQ name

This is needed because our built-ins can be loaded with two different
mechanisms (deserialization and lazy resolve) and, when that happens,
corresponding descriptors aren't equal to each other, so one of two resolved
descriptors for Any (or the same with Nothing) was never considered to be a
"special class" with no supertypes
Create fake overrides for deserialized enum class object

Now that Any has members, we need to make sure fake overrides are properly
generated in every class descriptor we create automatically or manually.

This fixes DescriptorSerializationTestGenerated
Minor, move method closer to its usage
Fix rangeTo between Float and Long

Float.rangeTo(Long) and Long.rangeTo(Float) now both return FloatRange for
consistency with other binary operations between floats and longs which, in
turn, return float to be consistent with Java
Fix VerifyError on rangeTo on primitive types
Remove ClassLoaderIsolationUtil

Minimize usages of jet.* in Java code: this will help in migration of jet.* to
package kotlin. Since tests will work with fq names instead of Class<?>
instances from now on, ClassLoaderIsolationUtil is useless now (except for one
unrelated method, which was moved to CodegenTestUtil)
Minor, rename method
Include bootstrap runtime in the intermediate kotlin-compiler.jar

This allows Kotlin compiler to be compatible only with the version of runtime
it was built against. This is currently done only on the first cycle of our
bootstrap process (the final released compiler is still supposed to work
against a separately shipped runtime)