This reverts commit 95f9bcba.

* drop dependency on stdlib/alt-headers in the most tests
* assign to myEnvironment at most once in JetLiteFixture
* more tests do not compile runtime

attempt 2

test case:

===
class Aaa() {
    fun f() = 1
    fun <P> f() = 1
}
===

===
fun ff() = 1

fun Int.ff() = 1
===

===
fun a() {}
fun a() {}
===

must be an error.

since JetTestCase is no longer a base class for any tests, remove code which is now redundant and rename it to JetTestCaseBuilder

Renderers in errors.
Constructor parameters are not properties unless otherwise specified