Revert "Don't ignore R8 warnings for optimized targets"

This reverts commit 5c2a1f3bda94df38e3f13e20bdbf080c0472ed2a.

Reason for revert: This change is causing the build to break, see http://b/268404998

Change-Id: I9173d1aa42846831123273ef7651940f2b0d6608
diff --git a/java/dex.go b/java/dex.go
index 6b7a7f0..b6fe109 100644
--- a/java/dex.go
+++ b/java/dex.go
@@ -43,8 +43,7 @@
 		// True if the module containing this has it set by default.
 		EnabledByDefault bool `blueprint:"mutated"`
 
-		// Whether to continue building even if warnings are emitted.  Defaults to true unless bytecode
-		// optimizations are enabled, in which case warnings are not ignored for safety.
+		// Whether to continue building even if warnings are emitted.  Defaults to true.
 		Ignore_warnings *bool
 
 		// If true, runs R8 in Proguard compatibility mode (default).
@@ -340,9 +339,8 @@
 	}
 
 	// TODO(b/180878971): missing classes should be added to the relevant builds.
-	// TODO(b/229727645): do not use true as default for unoptimized platform targets.
-	ignoreWarningsDefault := !Bool(opt.Optimize)
-	if proptools.BoolDefault(opt.Ignore_warnings, ignoreWarningsDefault) {
+	// TODO(b/229727645): do not use true as default for Android platform builds.
+	if proptools.BoolDefault(opt.Ignore_warnings, true) {
 		r8Flags = append(r8Flags, "-ignorewarnings")
 	}