IR text tests: Don't dump signatures for local declarations

1. Local declarations don't participate in IR-linkage, because they
can be referenced only inside the same body -> can be dropped
from IR text tests.

2. Mangled names for private declarations computed by descriptors/fir
are actually not used anywhere (they are recomputed by IR
immediately before serialization of IR). But sometimes such
mangled names diverge between K1 and K2 -> don't check them, but
always check mangled names computed by IR even for private
declarations.

3. Also: Drop DUMP_LOCAL_DECLARATION_SIGNATURES test directive.

^KT-57428 Obsolete
^KT-57430 Obsolete
^KT-57434 Obsolete
^KT-57778 Obsolete
^KT-57775 Obsolete

compiler/testData/ir/irText/declarations/provideDelegate/local.sig.kt.txt

@@ -7,7 +7,6 @@ class Delegate {
   //   Public signature: /Delegate.value|1987073854177347439[0]
   //   Public signature debug description: {}value
   val value: String
-    field
     // CHECK JVM_IR:
     //   Mangled name: Delegate#<get-value>(){}kotlin.String
     //   Public signature: /Delegate.value.<get-value>|-7202092821145242726[0]
@@ -45,7 +44,6 @@ class DelegateProvider {
   //   Public signature: /DelegateProvider.value|1987073854177347439[0]
   //   Public signature debug description: {}value
   val value: String
-    field
     // CHECK JVM_IR:
     //   Mangled name: DelegateProvider#<get-value>(){}kotlin.String
     //   Public signature: /DelegateProvider.value.<get-value>|-7202092821145242726[0]
@@ -79,11 +77,4 @@ class DelegateProvider {
 //   Public signature: /foo|-1041209573719867811[0]
 //   Public signature debug description: foo(){}
 fun foo(): Unit
-  // CHECK JVM_IR:
-  //   Mangled name: #foo(){}#<get-testMember>#static(){}kotlin.String
-  //   Mangled name for the signature: foo(){}<get-testMember>#static(){}kotlin.String
-  // CHECK JS_IR NATIVE:
-  //   Mangled name: #foo(){}#<get-testMember>#static(){}
-  //   Mangled name for the signature: foo(){}<get-testMember>#static(){}
-  local fun <get-testMember>(): String