spec-test-script/runtest.py: --size-level=0 for x86-64

with the recent version of LLVM, wamrc --size-level=1 often
generates R_X86_64_32S relocations, often for jump tables.

those relocations often fail on load with the infamous error:
"relocation truncated to fit R_X86_64_32S failed"

this commit workarounds it with --size-level=0.

an alternative is to disable jump tables.

cf. #3035

it might be better to do this in wamrc itself. however, currently
target info is not available there in case of native compilation.
related: #3356

Author: yamt

tests/wamr-test-suites/spec-test-script/runtest.py

@@ -46,7 +46,8 @@
 aot_target_options_map = {
     "i386": ["--target=i386"],
     "x86_32": ["--target=i386"],
-    "x86_64": ["--target=x86_64", "--cpu=skylake"],
+    # cf. https://github.com/bytecodealliance/wasm-micro-runtime/issues/3035
+    "x86_64": ["--target=x86_64", "--cpu=skylake", "--size-level=0"],
     "aarch64": ["--target=aarch64", "--target-abi=eabi", "--cpu=cortex-a53"],
     "aarch64_vfp": ["--target=aarch64", "--target-abi=gnueabihf", "--cpu=cortex-a53"],
     "armv7": ["--target=armv7", "--target-abi=eabi", "--cpu=cortex-a9", "--cpu-features=-neon"],