[K/JS] Add flag for disabling signature uniqueness checks at klib generating phase

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/klib.kt

@@ -734,6 +734,7 @@ fun serializeModuleIntoKlib(
     val compatibilityMode = CompatibilityMode(abiVersion)
     val sourceBaseDirs = configuration[CommonConfigurationKeys.KLIB_RELATIVE_PATH_BASES] ?: emptyList()
     val absolutePathNormalization = configuration[CommonConfigurationKeys.KLIB_NORMALIZE_ABSOLUTE_PATH] ?: false
+    val signatureClashChecks = configuration[CommonConfigurationKeys.PRODUCE_KLIB_SIGNATURES_CLASH_CHECKS] ?: false
 
     val serializedIr =
         JsIrModuleSerializer(
@@ -743,7 +744,8 @@ fun serializeModuleIntoKlib(
             compatibilityMode,
             skipExpects = !configuration.expectActualLinker,
             normalizeAbsolutePaths = absolutePathNormalization,
-            sourceBaseDirs = sourceBaseDirs
+            sourceBaseDirs = sourceBaseDirs,
+            signatureClashChecks
         ).serializedIrModule(moduleFragment)
 
     val moduleDescriptor = moduleFragment.descriptor

compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/lower/serialization/ir/JsIrModuleSerializer.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.ir.backend.js.lower.serialization.ir
 
 import org.jetbrains.kotlin.backend.common.serialization.CompatibilityMode
 import org.jetbrains.kotlin.backend.common.serialization.DeclarationTable
+import org.jetbrains.kotlin.backend.common.serialization.IdSignatureClashTracker
 import org.jetbrains.kotlin.backend.common.serialization.IrModuleSerializer
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.ir.IrBuiltIns
@@ -21,10 +22,14 @@ class JsIrModuleSerializer(
     compatibilityMode: CompatibilityMode,
     val skipExpects: Boolean,
     normalizeAbsolutePaths: Boolean,
-    sourceBaseDirs: Collection<String>
+    sourceBaseDirs: Collection<String>,
+    shouldCheckSignaturesOnUniqueness: Boolean = true
 ) : IrModuleSerializer<JsIrFileSerializer>(messageLogger, compatibilityMode, normalizeAbsolutePaths, sourceBaseDirs) {
 
-    private val globalDeclarationTable = JsGlobalDeclarationTable(irBuiltIns)
+    private val globalDeclarationTable = JsGlobalDeclarationTable(
+        irBuiltIns,
+        if (shouldCheckSignaturesOnUniqueness) JsUniqIdClashTracker() else IdSignatureClashTracker.DEFAULT_TRACKER
+    )
 
     override fun createSerializerForFile(file: IrFile): JsIrFileSerializer =
         JsIrFileSerializer(