Refactor module usages in HeaderImplDeclarationChecker

Instead of a vague name "moduleToCheck", use explicit names
"commonModule" and "platformModule".

idea/idea-analysis/src/org/jetbrains/kotlin/idea/highlighter/PlatformHeaderAnnotator.kt

@@ -54,7 +54,6 @@ class PlatformHeaderAnnotator : Annotator {
         val descriptor = declaration.toDescriptor() as? MemberDescriptor ?: return Diagnostics.EMPTY
         if (!descriptor.isHeader) return Diagnostics.EMPTY
 
-        val checkers = modulesToCheck.map(::HeaderImplDeclarationChecker)
         val diagnosticList = mutableListOf<Diagnostic>()
         val diagnosticSink = object : DiagnosticSink {
             override fun report(diagnostic: Diagnostic) {
@@ -63,8 +62,10 @@ class PlatformHeaderAnnotator : Annotator {
 
             override fun wantsDiagnostics() = true
         }
-        for (checker in checkers) {
-            checker.checkHeaderDeclarationHasImplementation(declaration, descriptor, diagnosticSink, checkImpl = false)
+        for (module in modulesToCheck) {
+            HeaderImplDeclarationChecker.checkHeaderDeclarationHasImplementation(
+                    declaration, descriptor, diagnosticSink, module, checkImpl = false
+            )
         }
 
         val suppressionCache = KotlinCacheService.getInstance(declaration.project).getSuppressionCache()

idea/src/org/jetbrains/kotlin/idea/highlighter/markers/DeclaredHeaderMarker.kt

@@ -51,8 +51,8 @@ private enum class SourceKind { NONE, PRODUCTION, TEST }
 fun ModuleDescriptor.hasDeclarationOf(descriptor: MemberDescriptor) = declarationOf(descriptor) != null
 
 private fun ModuleDescriptor.declarationOf(descriptor: MemberDescriptor): DeclarationDescriptor? =
-        with(HeaderImplDeclarationChecker(this)) {
-            descriptor.findCompatibleHeaderForImpl().firstOrNull()
+        with(HeaderImplDeclarationChecker) {
+            descriptor.findCompatibleHeaderForImpl(this@declarationOf).firstOrNull()
         }
 
 fun getHeaderDeclarationTooltip(declaration: KtDeclaration): String? {

idea/src/org/jetbrains/kotlin/idea/highlighter/markers/ImplementedHeaderMarker.kt

@@ -34,8 +34,8 @@ fun ModuleDescriptor.hasImplementationsOf(descriptor: MemberDescriptor) =
         implementationsOf(descriptor).isNotEmpty()
 
 private fun ModuleDescriptor.implementationsOf(descriptor: MemberDescriptor): List<DeclarationDescriptor> =
-        with(HeaderImplDeclarationChecker(this)) {
-            descriptor.findCompatibleImplForHeader()
+        with(HeaderImplDeclarationChecker) {
+            descriptor.findCompatibleImplForHeader(this@implementationsOf)
         }
 
 fun getPlatformImplementationTooltip(declaration: KtDeclaration): String? {