JavaScriptKit: import Android module for non-Wasm Android targets (#722)

Building JavaScriptKit for the Swift 6.3 Android SDK triples
(e.g. aarch64-unknown-linux-android28, x86_64-unknown-linux-android30)
fails in ThreadLocal.swift with:

    error: cannot find 'pthread_key_create' in scope
    error: cannot find 'pthread_key_t' in scope

Android uses Bionic, exposed to Swift as the `Android` module, rather
than Glibc. The existing conditional falls through to
`#error("Unsupported platform")` on Android.

Add a `canImport(Android)` branch between the Darwin and Glibc
branches, matching the pattern already used by Foundation and
swift-corelibs-libdispatch. No Wasm, Darwin, or Glibc behavior
changes.

Author: ken0nek

Sources/JavaScriptKit/ThreadLocal.swift

@@ -4,6 +4,8 @@ import wasi_pthread
 #endif
 #elseif canImport(Darwin)
 import Darwin
+#elseif canImport(Android)
+import Android
 #elseif canImport(Glibc)
 import Glibc
 #else