Replace panic with ModuleErrorf

This is a followup cleanup for aosp/2876754 and replaces panic with
ctx.ModuleErrorf. The latter creates a more expressive build error.

Implementation details
- export moduleErrorf interface from build/soong/android. This minimal
  interface will be used as a parameter for `DexJarBuildPath`
- Add ModuleErrorf to the function signature of DexJarBuildPath. This
  parameter only gets used for Import and SdkLibraryImport structs.
  These two can have duplicate deapexer definitions, and ModuleErrorf
  will be used to report that error
- Create a minimal implementation of `ModuleErrorf` in tests of java and
  apex

Test: m nothing --no-skip-soong-tests
Change-Id: I0febec651f40c3f04deb957e64133c94b80fbd78
diff --git a/apex/apex.go b/apex/apex.go
index 42a7d73..4dd7728 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -1628,7 +1628,7 @@
 type javaModule interface {
 	android.Module
 	BaseModuleName() string
-	DexJarBuildPath() java.OptionalDexJarPath
+	DexJarBuildPath(ctx android.ModuleErrorfContext) java.OptionalDexJarPath
 	JacocoReportClassesFile() android.Path
 	LintDepSets() java.LintDepSets
 	Stem() string
@@ -1642,7 +1642,7 @@
 
 // apexFileForJavaModule creates an apexFile for a java module's dex implementation jar.
 func apexFileForJavaModule(ctx android.BaseModuleContext, module javaModule) apexFile {
-	return apexFileForJavaModuleWithFile(ctx, module, module.DexJarBuildPath().PathOrNil())
+	return apexFileForJavaModuleWithFile(ctx, module, module.DexJarBuildPath(ctx).PathOrNil())
 }
 
 // apexFileForJavaModuleWithFile creates an apexFile for a java module with the supplied file.