Skip install rules for apexes with installable: false

When an apex sets installable: false call SkipInstall to prevent
creating the install rules, and don't report the install rules
to Make.

Fixes: 221261079
Test: m checkbuild
Change-Id: If94759b16f79ee10ddcf8ee89603ca9e822b74f5
diff --git a/apex/androidmk.go b/apex/androidmk.go
index 8785ca0..059b4d7 100644
--- a/apex/androidmk.go
+++ b/apex/androidmk.go
@@ -373,8 +373,10 @@
 				}
 				fmt.Fprintln(w, "LOCAL_MODULE_STEM :=", name+stemSuffix)
 				fmt.Fprintln(w, "LOCAL_UNINSTALLABLE_MODULE :=", !a.installable())
-				fmt.Fprintln(w, "LOCAL_SOONG_INSTALLED_MODULE :=", a.installedFile.String())
-				fmt.Fprintln(w, "LOCAL_SOONG_INSTALL_PAIRS :=", a.outputFile.String()+":"+a.installedFile.String())
+				if a.installable() {
+					fmt.Fprintln(w, "LOCAL_SOONG_INSTALLED_MODULE :=", a.installedFile.String())
+					fmt.Fprintln(w, "LOCAL_SOONG_INSTALL_PAIRS :=", a.outputFile.String()+":"+a.installedFile.String())
+				}
 
 				// Because apex writes .mk with Custom(), we need to write manually some common properties
 				// which are available via data.Entries