Refactor sanitized library on-disk layout - Soong.

This CL moves the location of ASAN-ified libraries on disk in the
following manner:
/data/lib* --> /data/asan/system/lib*
/data/vendor/* --> /data/asan/vendor/*

There are a couple of advantages to this, including better isolation
from other components, and more transparent linker renaming and
SELinux policies.

Bug: 36574794
Bug: 36674745
Test: m -j40 && SANITIZE_TARGET="address" m -j40 and the device
boots. All sanitized libraries are correctly located in /data/asan/*.

Change-Id: I06bf459260ec451d4495a02562f640ad622f34c2
diff --git a/cc/installer.go b/cc/installer.go
index 64f87d9..c4de589 100644
--- a/cc/installer.go
+++ b/cc/installer.go
@@ -30,8 +30,9 @@
 type installLocation int
 
 const (
-	InstallInSystem installLocation = 0
-	InstallInData                   = iota
+	InstallInSystem       installLocation = 0
+	InstallInData                         = iota
+	InstallInSanitizerDir                 = iota
 )
 
 func NewBaseInstaller(dir, dir64 string, location installLocation) *baseInstaller {
@@ -78,6 +79,10 @@
 	return installer.location == InstallInData
 }
 
+func (installer *baseInstaller) inSanitizerDir() bool {
+	return installer.location == InstallInSanitizerDir
+}
+
 func (installer *baseInstaller) hostToolPath() android.OptionalPath {
 	return android.OptionalPath{}
 }