Friendly error message on apex_available and min_sdk_version checks

1) suggest a fix at the end of the message
2) add new lines around the dependency path so that they are visually
separated from rest of the error message

Bug: N/A
Test: m with an intentional break
error: bionic/apex/Android.bp:32:1: module "com.android.runtime" variant "android_common_com.android.runtime_image": "libutils_headers" requires "libsystem_headers" that doesn't list the APEX under 'apex_available'.

Dependency path:
           via tag apex.dependencyTag: { name:executable payload:true}
    -> crash_dump{os:android,image:,arch:arm_armv8-a,sdk:,apex:apex10000}
           via tag cc.libraryDependencyTag: { Kind:staticLibraryDependency Order:normalLibraryDependency wholeStatic:false reexportFlags:false explicitlyVersioned:false dataLib:false ndk:false staticUnwinder:false makeSuffix: skipApexAllowedDependenciesCheck:false excludeInApex:false}
    -> libtombstoned_client_static{os:android,image:,arch:arm_armv8-a,sdk:,link:static,apex:apex10000}
           via tag cc.libraryDependencyTag: { Kind:staticLibraryDependency Order:normalLibraryDependency wholeStatic:true reexportFlags:true explicitlyVersioned:false dataLib:false ndk:false staticUnwinder:false makeSuffix: skipApexAllowedDependenciesCheck:false excludeInApex:false}
    -> libcutils{os:android,image:,arch:arm_armv8-a,sdk:,link:static,asan:,apex:apex10000}
           via tag cc.libraryDependencyTag: { Kind:headerLibraryDependency Order:normalLibraryDependency wholeStatic:false reexportFlags:false explicitlyVersioned:false dataLib:false ndk:false staticUnwinder:false makeSuffix: skipApexAllowedDependenciesCheck:false excludeInApex:false}
    -> libutils_headers{os:android,image:,arch:arm_armv8-a,sdk:,asan:,apex:apex10000}
           via tag cc.libraryDependencyTag: { Kind:headerLibraryDependency Order:normalLibraryDependency wholeStatic:false reexportFlags:true explicitlyVersioned:false dataLib:false ndk:false staticUnwinder:false makeSuffix: skipApexAllowedDependenciesCheck:false excludeInApex:false}
    -> libsystem_headers{os:android,image:,arch:arm_armv8-a,sdk:,asan:,apex:apex10000}

Consider adding "com.android.runtime" to 'apex_available' property of "libsystem_headers"

Change-Id: I09f92c3086ea433780133a33ba0ad73baee6dc41
diff --git a/apex/apex_test.go b/apex/apex_test.go
index 3f56047..c90b928 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -5184,7 +5184,7 @@
 
 func TestApexAvailable_IndirectDep(t *testing.T) {
 	// libbbaz is an indirect dep
-	testApexError(t, `requires "libbaz" that doesn't list the APEX under 'apex_available'. Dependency path:
+	testApexError(t, `requires "libbaz" that doesn't list the APEX under 'apex_available'.\n\nDependency path:
 .*via tag apex\.dependencyTag.*name:sharedLib.*
 .*-> libfoo.*link:shared.*
 .*via tag cc\.libraryDependencyTag.*Kind:sharedLibraryDependency.*