Revert "Add BUILD_BROKEN_DONT_CHECK_SYSTEMSDK"

Revert submission 2897682-dont_limit_systemsdk

Reason for revert: blocking revert for 318695834

Bug:318695834

Reverted changes: /q/submissionid:2897682-dont_limit_systemsdk

Change-Id: I4cf7268cba21c7b81b406c91240bb98190fa4ebc
diff --git a/android/sdk_version.go b/android/sdk_version.go
index 73568af..9c84a27 100644
--- a/android/sdk_version.go
+++ b/android/sdk_version.go
@@ -306,7 +306,7 @@
 func (s SdkSpec) ValidateSystemSdk(ctx EarlyModuleContext) bool {
 	// Do some early checks. This check is currently only for Java modules. And our only concern
 	// is the use of "system" SDKs.
-	if !isJava(ctx.Module()) || s.Kind != SdkSystem || ctx.DeviceConfig().BuildBrokenDontCheckSystemSdk() {
+	if !isJava(ctx.Module()) || s.Kind != SdkSystem {
 		return true
 	}