Avoid irGet with Unit value if it is last it IrReturnableBlock

This is needed to pass `MethodVerifier` check on JVM backend

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/ReturnableBlockLowering.kt

@@ -18,6 +18,7 @@ import org.jetbrains.kotlin.ir.expressions.impl.IrDoWhileLoopImpl
 import org.jetbrains.kotlin.ir.symbols.IrReturnableBlockSymbol
 import org.jetbrains.kotlin.ir.symbols.IrSymbol
 import org.jetbrains.kotlin.ir.transformStatement
+import org.jetbrains.kotlin.ir.types.isUnit
 
 // TODO migrate other usages and move this file to backend.jvm
 /**
@@ -158,7 +159,11 @@ class ReturnableBlockTransformer(val context: CommonBackendContext, val containe
             return builder.irBlock(expression, expression.origin) {
                 +variable
                 +loop
-                +irGet(variable)
+                if (!expression.type.isUnit()) {
+                    // In case of Unit return type we don't need to return an explicit value. This will not be optimized by JVM backend and
+                    // may result in exceptions in `MethodVerifier` before optimizations.
+                    +irGet(variable)
+                }
             }
         }
     }