KT-5248 Don't wrap variable if it is captured only in inlined closures

Remove non-escaping Ref's on bytecode postprocessing pass.

compiler/testData/codegen/bytecodeText/capturedVarsOptimization/sharedSlotsWithCapturedVars.kt

@@ -0,0 +1,32 @@
+// WITH_RUNTIME
+
+fun box(): String {
+    run {
+        run {
+            var x1 = 0
+            run { ++x1 }
+            if (x1 == 0) return "fail"
+        }
+
+        run {
+            var x2 = 0
+            run { x2++ }
+            if (x2 == 0) return "fail"
+        }
+    }
+
+    return "OK"
+}
+
+
+// Shared variable slots (x1, x2):
+// 5 ILOAD 0
+// 4 ISTORE 0
+
+// Temporary variable slots for 'x2++':
+// 1 ILOAD 1
+// 1 ISTORE 1
+
+// 0 NEW
+// 0 GETFIELD
+// 0 PUTFIELD