[flags] Reduce alignment to 4kB on Android

The previous CL (https://crrev.com/c/3810187) caused a 86.9kB binary
size regression on arm64 Android.
The 64kB alignment is actually only needed on Linux, as Android
always uses 4kB. This reduces the binary size by 98.3kB in a local test,
resulting in a 11.4kB reduction overall (over both patches).

R=cbruni@chromium.org

Bug: v8:12887
Change-Id: If0c44d1b447e6982876a6ced8680b904613e39d5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3829473Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82503}

src/base/build_config.h

@@ -73,8 +73,9 @@ constexpr int kPageSizeBits = 18;
 #if defined(V8_OS_MACOS) && defined(V8_HOST_ARCH_ARM64)
 // MacOS on arm64 uses 16kB pages.
 constexpr int kMinimumOSPageSize = 16 * 1024;
-#elif defined(V8_OS_LINUX) && defined(V8_HOST_ARCH_ARM64)
-// Linux on arm64 can be configured for up to 64kB pages.
+#elif defined(V8_OS_LINUX) && !defined(V8_OS_ANDROID) && \
+    defined(V8_HOST_ARCH_ARM64)
+// Linux on arm64 (excluding android) can be configured for up to 64kB pages.
 constexpr int kMinimumOSPageSize = 64 * 1024;
 #else
 // Everything else uses 4kB pages.