Remove --noexperimental_platform_in_output_dir

This is a followup to aosp/2606989.

This flag is not necessary now that we're using one platform name
for all of mixed builds.

Also rename current_product to mixed_builds_product so that it's clear
that that this platform should only be used for mixed builds.

In addition, make the bazelrc files point to the named products again
instead of the mixed build product so that b builds will still have
qualified outputs, but mixed builds won't.

Test: Presubmit and kernel build tools abtd run
Change-Id: I7f764cf42cd1323f4b495d1320931f59a076ac63
diff --git a/android/bazel_handler.go b/android/bazel_handler.go
index 28bcace..4645e6b 100644
--- a/android/bazel_handler.go
+++ b/android/bazel_handler.go
@@ -689,26 +689,20 @@
 
 func (context *mixedBuildBazelContext) createBazelCommand(config Config, runName bazel.RunName, command bazelCommand,
 	extraFlags ...string) bazel.CmdRequest {
+	if runtime.GOOS != "linux" && runtime.GOOS != "darwin" {
+		panic("Unknown GOOS: " + runtime.GOOS)
+	}
 	cmdFlags := []string{
 		"--output_base=" + absolutePath(context.paths.outputBase),
 		command.command,
 		command.expression,
 		"--profile=" + shared.BazelMetricsFilename(context.paths, runName),
 
-		// We don't need to set --host_platforms because it's set in bazelrc files
-		// that the bazel shell script wrapper passes
-
-		// Optimize Ninja rebuilds by ensuring Bazel write into product-agnostic
-		// output paths for the configured targets that shouldn't be affected by
-		// TARGET_PRODUCT. Otherwise product agnostic modules will be rebuilt by
-		// Ninja when the product changes, unconditionally.
-		//
-		// For example, Mainline APEXes should be identical regardless of the
-		// product (modulo arch/cpu).
-		//
-		// This flag forcibly disables the platform prefix in the intermediate
-		// outputs during a mixed build.
-		"--noexperimental_platform_in_output_dir",
+		"--host_platform=@soong_injection//product_config_platforms:mixed_builds_product-" + context.targetBuildVariant + "_" + runtime.GOOS + "_x86_64",
+		// Don't specify --platforms, because on some products/branches (like kernel-build-tools)
+		// the main platform for mixed_builds_product-variant doesn't exist because an arch isn't
+		// specified in product config. The derivative platforms that config_node transitions into
+		// will still work.
 
 		// Suppress noise
 		"--ui_event_filters=-INFO",
@@ -755,9 +749,9 @@
 #####################################################
 def _config_node_transition_impl(settings, attr):
     if attr.os == "android" and attr.arch == "target":
-        target = "current_product-{VARIANT}"
+        target = "mixed_builds_product-{VARIANT}"
     else:
-        target = "current_product-{VARIANT}_%s_%s" % (attr.os, attr.arch)
+        target = "mixed_builds_product-{VARIANT}_%s_%s" % (attr.os, attr.arch)
     apex_name = ""
     if attr.within_apex:
         # //build/bazel/rules/apex:apex_name has to be set to a non_empty value,
@@ -994,9 +988,9 @@
   platform_name = platforms[0].name
   if platform_name == "host":
     return "HOST"
-  if not platform_name.startswith("current_product-{TARGET_BUILD_VARIANT}"):
-    fail("expected platform name of the form 'current_product-{TARGET_BUILD_VARIANT}_android_<arch>' or 'current_product-{TARGET_BUILD_VARIANT}_linux_<arch>', but was " + str(platforms))
-  platform_name = platform_name.removeprefix("current_product-{TARGET_BUILD_VARIANT}").removeprefix("_")
+  if not platform_name.startswith("mixed_builds_product-{TARGET_BUILD_VARIANT}"):
+    fail("expected platform name of the form 'mixed_builds_product-{TARGET_BUILD_VARIANT}_android_<arch>' or 'mixed_builds_product-{TARGET_BUILD_VARIANT}_linux_<arch>', but was " + str(platforms))
+  platform_name = platform_name.removeprefix("mixed_builds_product-{TARGET_BUILD_VARIANT}").removeprefix("_")
   config_key = ""
   if not platform_name:
     config_key = "target|android"
@@ -1005,7 +999,7 @@
   elif platform_name.startswith("linux_"):
     config_key = platform_name.removeprefix("linux_") + "|linux"
   else:
-    fail("expected platform name of the form 'current_product-{TARGET_BUILD_VARIANT}_android_<arch>' or 'current_product-{TARGET_BUILD_VARIANT}_linux_<arch>', but was " + str(platforms))
+    fail("expected platform name of the form 'mixed_builds_product-{TARGET_BUILD_VARIANT}_android_<arch>' or 'mixed_builds_product-{TARGET_BUILD_VARIANT}_linux_<arch>', but was " + str(platforms))
 
   within_apex = buildoptions.get("//build/bazel/rules/apex:within_apex")
   apex_sdk_version = buildoptions.get("//build/bazel/rules/apex:min_sdk_version")