[mpp] Test that every deprecated pre-HMPP property triggers an Error

Previously all these properties were put together, so only one
of them could have triggered the Error

#KT-59304 Verification Pending

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/mpp/MppDiagnosticsIt.kt

@@ -26,15 +26,12 @@ class MppDiagnosticsIt : KGPBaseTest() {
 
     @GradleTest
     fun testDeprecatedMppProperties(gradleVersion: GradleVersion) {
+        for (deprecatedProperty in this.deprecatedFlags) {
             project("mppDeprecatedProperties", gradleVersion) {
                 checkDeprecatedProperties(isDeprecationExpected = false)
 
                 this.gradleProperties.appendText(
-                defaultFlags.entries.joinToString(
+                    "${deprecatedProperty.key}=${deprecatedProperty.value}${System.lineSeparator()}"
-                    prefix = System.lineSeparator(),
-                    postfix = System.lineSeparator(),
-                    separator = System.lineSeparator(),
-                ) { (prop, value) -> "$prop=$value" }
                 )
                 checkDeprecatedProperties(isDeprecationExpected = true)
 
@@ -46,6 +43,7 @@ class MppDiagnosticsIt : KGPBaseTest() {
                 checkDeprecatedProperties(isDeprecationExpected = false)
             }
         }
+    }
 
     @GradleTest
     fun testErrorDiagnosticBuildFails(gradleVersion: GradleVersion) {
@@ -202,7 +200,7 @@ class MppDiagnosticsIt : KGPBaseTest() {
         }
     }
 
-    private val defaultFlags: Map<String, String>
+    private val deprecatedFlags: Map<String, String>
         get() = mapOf(
             "kotlin.mpp.enableGranularSourceSetsMetadata" to "true",
             "kotlin.mpp.enableCompatibilityMetadataVariant" to "false",