Update naming of platforms subdir

The build system previously named the platforms subdir by
PLATFORM_VERSION, which is 13 for android 13, aka T, so the subdir
name would be android-13.

Android studio installs the SDK into a subdir identified by the api
level, so android-33 for android T, and also the extension api level
for extension SDKs, e.g. android-33-ext4.

Update the build system subdir name to match the android studio install
path, in order to avoid confusion and make it simpler to just unzip
a built SDK into the platforms dir, avoiding the need to provide a
package.xml file for studio to install it correctly.

Bug: 254023524
Test: m sdk sdk_repo dist, verify subdir is android-33 in:
   $ zipinfo -1 out/dist/android-sdk_eng.hansson_linux-x86.zip \
     | cut -f 1-3 -d '/' | grep platforms | sort | uniq
Change-Id: I1d3a7fd4c480859c28cdcbcb8c0cf2800ac4a1d7

core/Makefile

@@ -6824,7 +6824,11 @@ $(INTERNAL_SDK_TARGET): PRIVATE_NAME := $(sdk_name)
 $(INTERNAL_SDK_TARGET): PRIVATE_DIR := $(sdk_dir)/$(sdk_name)
 $(INTERNAL_SDK_TARGET): PRIVATE_DEP_FILE := $(sdk_dep_file)
 $(INTERNAL_SDK_TARGET): PRIVATE_INPUT_FILES := $(sdk_atree_files)
-
+$(INTERNAL_SDK_TARGET): PRIVATE_PLATFORM_NAME := \
+  $(strip $(if $(filter $(PLATFORM_SDK_EXTENSION_VERSION),$(PLATFORM_BASE_SDK_EXTENSION_VERSION)),\
+    android-$(PLATFORM_SDK_VERSION),\
+    android-$(PLATFORM_SDK_VERSION)-ext$(PLATFORM_SDK_EXTENSION_VERSION)) \
+)
 # Set SDK_GNU_ERROR to non-empty to fail when a GNU target is built.
 #
 #SDK_GNU_ERROR := true
@@ -6849,7 +6853,7 @@ $(INTERNAL_SDK_TARGET): $(deps)
 	        -I $(PRODUCT_OUT) \
 	        -I $(HOST_OUT) \
 	        -I $(TARGET_COMMON_OUT_ROOT) \
-	        -v "PLATFORM_NAME=android-$(PLATFORM_VERSION)" \
+	        -v "PLATFORM_NAME=$(PRIVATE_PLATFORM_NAME)" \
 	        -v "OUT_DIR=$(OUT_DIR)" \
 	        -v "HOST_OUT=$(HOST_OUT)" \
 	        -v "TARGET_ARCH=$(TARGET_ARCH)" \