Reland Add microdroid_16k

So far only non-protected VMs can boot with 16k kernel.

Support for microdroid_16k pvms is tracked in b/376870129.

Bug: 317201718
Bug: 376517173
Bug: 333730505
Bug: 376870129
Test: adb shell /apex/com.android.virt/bin/vm run-microdroid \
    --os microdroid_16k \
    --debug full
Test: atest MicrodropidTests
Test: atest MicrodroidHostTestCases
Test: atest virtualizationmanager_device_test
Test: presubmit
Change-Id: I0fe5cd431b16f57e5bcc51146691fd0368d30818
diff --git a/build/microdroid/bootconfig.x86_64_16k b/build/microdroid/bootconfig.x86_64_16k
new file mode 100644
index 0000000..6a8423b
--- /dev/null
+++ b/build/microdroid/bootconfig.x86_64_16k
@@ -0,0 +1 @@
+page_shift=14