support/testing: TestClangCompilerRT: Add a kernel fragment for 48 bits virtual adress

Add a kernel fragment to enable
CONFIG_ARM64_VA_BITS_48 for the AARCH64 QEMU platform in the
clang compiler -rt runtime test.

Without this setting, this sanitize-based test fails with clang-20
due to insufficient virtual adress space.

"This might potentially affect ARM platforms with 39-bit address space." from [1]

[1] https://github.com/llvm/llvm-project/commit/a588cfe37ea36ec4fae35a233a13d3557fba86e9

Signed-off-by: El Mehdi YOUNES <elmehdi.younes@smile.fr>
Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Julien Olivain <ju.o@free.fr>

support/testing/tests/package/test_clang.py

@@ -7,8 +7,10 @@ FUZZ_TIMEOUT = 120
 
 class TestClangCompilerRT(infra.basetest.BRTest):
     br2_external = [infra.filepath("tests/package/br2-external/clang-compiler-rt")]
+    # Without this option the test fails due to insufficient address space for 64-bit allocator
+    va48_fragment = infra.filepath("tests/package/test_clang/linux-arm64-va48.fragment")
     config = \
-        """
+        f"""
         BR2_aarch64=y
         BR2_TOOLCHAIN_EXTERNAL=y
         BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"
@@ -17,6 +19,7 @@ class TestClangCompilerRT(infra.basetest.BRTest):
         BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.19.283"
         BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
         BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/aarch64-virt/linux.config"
+        BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="{va48_fragment}"
         BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
         BR2_PACKAGE_COMPILER_RT=y
         BR2_PACKAGE_LLVM=y

support/testing/tests/package/test_clang/linux-arm64-va48.fragment

@@ -0,0 +1 @@
+CONFIG_ARM64_VA_BITS_48=y