Build aapt2 statically on windows

Prebuilt script is no longer updating libwinpthread-1.dll. Link the
windows executable statically so aapt2 will no longer require the
dependency on the dll.

Bug: 131883685
Test: manual test of aapt2.exe on windows without libwinpthread-1.dll
Change-Id: If78a8ec3030003862c18e3967e4d8333fde7928a

tools/aapt2/Android.bp

@@ -41,6 +41,7 @@ cc_defaults {
         windows: {
             enabled: true,
             cflags: ["-Wno-maybe-uninitialized"],
+            ldflags: ["-static"],
         },
         darwin: {
             cflags: ["-D_DARWIN_UNLIMITED_STREAMS"],