Simplify interpretation of CROSS_BUILD_DIR

Co-authored-by: Malcolm Smith <smith@chaquo.com>

Author: freakboy3742

Android/testbed/app/build.gradle.kts

@@ -8,9 +8,7 @@ plugins {
 
 val ANDROID_DIR = file("../..")
 val PYTHON_DIR = ANDROID_DIR.parentFile!!
-val CROSS_BUILD_DIR = System.getenv("CROSS_BUILD_DIR") ?: "cross-build"
-val PYTHON_CROSS_DIR = file(
-    if ((File(CROSS_BUILD_DIR)).isAbsolute) CROSS_BUILD_DIR else "$PYTHON_DIR/$CROSS_BUILD_DIR"
+val PYTHON_CROSS_DIR = file(System.getenv("CROSS_BUILD_DIR") ?: "$PYTHON_DIR/cross-build")
 )
 val inSourceTree = (
     ANDROID_DIR.name == "Android" && file("$PYTHON_DIR/pyconfig.h.in").exists()