JVM_IR: move const initialization handling to lowering

Had to edit some bytecodeText tests to account for the fact that JVM_IR
no longer generates explicit initializations for ConstantValue fields,
but NoConstantValueAttributeForNonConstVals is not the default yet.

compiler/testData/codegen/bytecodeText/constants/floatingPoints.kt

@@ -1,3 +1,4 @@
+// !LANGUAGE: +NoConstantValueAttributeForNonConstVals
 val a = 1.0 + 10
 val b = 2 + 10.0
 val c = 3.0F + 10