JVM_IR: defer some branch optimizations to codegen.

Specifically, defer the removal of hand-written "if (true|false)" from
JvmBuiltinOptimizationLowering into codegen so that appropriate debug
info (and a NOP) can be inserted.

Change-Id: Ia11af05ad8b4251946bd3e685fb7c3319f0f433f

compiler/testData/codegen/bytecodeText/lineNumbers/ifConsts.kt

@@ -0,0 +1,35 @@
+fun cond() = false
+
+fun bar() {}
+
+fun foo() {
+    if (cond()) {
+        bar()
+    } else if (true) {
+        bar()
+    } else {
+        bar()
+    }
+
+    if (false) {
+        bar()
+    } else if (true) {
+        bar()
+    } else {
+        bar()
+    }
+
+    if (true) {
+        bar()
+    } else if (false) {
+        bar()
+    } else {
+        bar()
+    }
+}
+
+// 1 LINENUMBER 6
+// 1 LINENUMBER 8
+// 1 LINENUMBER 14
+// 1 LINENUMBER 16
+// 1 LINENUMBER 22

compiler/testData/codegen/bytecodeText/lineNumbers/ifFalse.kt

@@ -0,0 +1,7 @@
+fun foo(): Int {
+    if (false) {
+        return 1
+    }
+    return 2
+}
+// 1 LINENUMBER 2

compiler/testData/codegen/bytecodeText/lineNumbers/ifFalseElse.kt

@@ -0,0 +1,8 @@
+fun foo(): Int {
+    if (false) {
+        return 1
+    } else {
+        return 2
+    }
+}
+// 1 LINENUMBER 2

compiler/testData/codegen/bytecodeText/lineNumbers/ifTrue.kt

@@ -0,0 +1,7 @@
+fun foo(): Int {
+    if (true) {
+        return 1
+    }
+    return 2
+}
+// 1 LINENUMBER 2

compiler/testData/codegen/bytecodeText/lineNumbers/ifTrueElse.kt

@@ -0,0 +1,8 @@
+fun foo(): Int {
+    if (true) {
+        return 1
+    } else {
+        return 2
+    }
+}
+// 1 LINENUMBER 2