Add partialcompileclean phony

When SOONG_USE_PARTIAL_COMPILE transitions from on to off, we need to
remove all files that may have been built using partial compile.

Bug: b/396145326
Test: manual, TH
Change-Id: I1d91f95883fd8b1d92731a490244a898f25e614d
diff --git a/ui/build/config.go b/ui/build/config.go
index 2a00c41..a4f778d 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -1685,6 +1685,10 @@
 	return filepath.Join(c.ProductOut(), "previous_build_config.mk")
 }
 
+func (c *configImpl) DevicePreviousUsePartialCompile() string {
+	return filepath.Join(c.ProductOut(), "previous_use_partial_compile.txt")
+}
+
 func (c *configImpl) KatiPackageMkDir() string {
 	return filepath.Join(c.SoongOutDir(), "kati_packaging"+c.KatiSuffix())
 }