Revert "Detect invalid arch specific properties in snapshot"

Revert submission 1302576

Bug: 156054601
Reason for revert: Presumed root cause of build break.
Reverted Changes:
Ifc8116e11:Detect invalid arch specific properties in snapsho...
I7ebd33307:Adds support for 'ignored-on-host'
I167b47a13:Fix snapshot of a host/device cc_library with stub...

Change-Id: Id7eba0bdde5c579e10e9b42d94a7cfab5f34995f
diff --git a/android/sdk.go b/android/sdk.go
index 36afc3d..873e089 100644
--- a/android/sdk.go
+++ b/android/sdk.go
@@ -342,15 +342,9 @@
 	//
 	// * The variant property structs are analysed to find exported (capitalized) fields which
 	//   have common values. Those fields are cleared and the common value added to the common
-	//   properties.
-	//
-	//   A field annotated with a tag of `sdk:"keep"` will be treated as if it
+	//   properties. A field annotated with a tag of `sdk:"keep"` will be treated as if it
 	//   was not capitalized, i.e. not optimized for common values.
 	//
-	//   A field annotated with a tag of `android:"arch_variant"` will be allowed to have
-	//   values that differ by arch, fields not tagged as such must have common values across
-	//   all variants.
-	//
 	// * The sdk module type populates the BpModule structure, creating the arch specific
 	//   structure and calls AddToPropertySet(...) on the properties struct to add the member
 	//   specific properties in the correct place in the structure.