[JVM_IR] Improve debugging behavior of inline functions

Specifically, this commit improves the stepping behavior of the IR
backend around functions with defaults.

  - Improved line numbers in the default handler itself for better
    stepping when inlined.

  - Improved source information on default arguments

  - Improved test coverage of stepping behavior in old and IR backends.

Improves the stepping behaviour around inline methods with default
arguments. In particular, we now accurately step through the
evaluation of default arguments, but do _not_ spuriously show the exit
from the $default handler.

compiler/testData/diagnostics/testsWithJvmBackend/duplicateJvmSignature/accidentalOverrides/defaultFunction_ir.kt

@@ -1,3 +1,4 @@
+// TARGET_BACKEND: JVM_IR
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
 open class Base {

compiler/testData/diagnostics/testsWithJvmBackend/duplicateJvmSignature/accidentalOverrides/defaultFunction_old.kt

@@ -0,0 +1,10 @@
+// TARGET_BACKEND: JVM_OLD
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+open class Base {
+    open fun `foo$default`(d: Derived, i: Int, mask: Int, mh: Any) {}
+}
+
+class Derived : Base() {
+    <!ACCIDENTAL_OVERRIDE!>fun foo(i: Int = 0)<!> {}
+}

compiler/testData/diagnostics/testsWithJvmBackend/duplicateJvmSignature/accidentalOverrides/defaultFunction_old.txt

@@ -0,0 +1,18 @@
+package
+
+public open class Base {
+    public constructor Base()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open fun `foo$default`(/*0*/ d: Derived, /*1*/ i: kotlin.Int, /*2*/ mask: kotlin.Int, /*3*/ mh: kotlin.Any): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class Derived : Base {
+    public constructor Derived()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(/*0*/ i: kotlin.Int = ...): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun `foo$default`(/*0*/ d: Derived, /*1*/ i: kotlin.Int, /*2*/ mask: kotlin.Int, /*3*/ mh: kotlin.Any): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/testsWithJvmBackend/duplicateJvmSignature/specialNames/defaults_ir.kt

@@ -1,3 +1,4 @@
+// TARGET_BACKEND: JVM_IR
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
 class C {

compiler/testData/diagnostics/testsWithJvmBackend/duplicateJvmSignature/specialNames/defaults_old.kt

@@ -0,0 +1,7 @@
+// TARGET_BACKEND: JVM_OLD
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+class C {
+    <!CONFLICTING_JVM_DECLARATIONS!>fun `a$default`(c: C, x: Int, m: Int, mh: Any)<!> {}
+    <!CONFLICTING_JVM_DECLARATIONS!>fun a(x: Int = 1)<!> {}
+}

compiler/testData/diagnostics/testsWithJvmBackend/duplicateJvmSignature/specialNames/defaults_old.txt

@@ -0,0 +1,10 @@
+package
+
+public final class C {
+    public constructor C()
+    public final fun a(/*0*/ x: kotlin.Int = ...): kotlin.Unit
+    public final fun `a$default`(/*0*/ c: C, /*1*/ x: kotlin.Int, /*2*/ m: kotlin.Int, /*3*/ mh: kotlin.Any): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}