Optimize coercion to Unit.

POP operations are backward-propagated.

Operation can't be transformed if its result is moved within stack
(by DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, or SWAP).

Unnecessary operations are replaced with NOPs (for debugger).
Unnecessary NOPs are removed.

KT-9922 Suboptimal generation for simple safe call with unused return value
KT-11116 Optimize methods returning Unit

compiler/testData/codegen/bytecodeText/coercionToUnitOptimization/tryInlined.kt

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+
+import java.io.*
+
+fun test(r: Reader) {
+    val ss = hashSetOf<String>()
+    r.useLines { it.forEach { ss.add(it) } }
+}
+
+// 2 POP