CI: Bump Ubuntu to 24.04-LTS

[jserv]

Ubuntu Linux 24.04 (noble) is the latest LTS release, and this commit updates the CI pipeline hosts and recommended development environments accordingly. The version of clang-format is updated to v18, with all C source files re-indented. LLVM is also upgraded to version 18.

[jserv]

The performance regression check failed because of the change of RISC-V directory layout. Hence, I have to make the following changes:

--- a/tests/coremark.py
+++ b/tests/coremark.py
@@ -14,7 +14,7 @@ if not file_exist:
     exit(1)
 print("Start Test CoreMark benchmark")
 comp_proc = subprocess.check_output(
-    "build/rv32emu build/coremark.elf {}".format(coremark_param), shell=True).decode("utf-8")
+    "build/rv32emu build/riscv32/coremark {}".format(coremark_param), shell=True).decode("utf-8")
 if not comp_proc or comp_proc.find("Error") != -1:
     print("Test Error")
     exit(1)
diff --git a/tests/dhrystone.sh b/tests/dhrystone.sh
index bc3a03e..6e8650d 100755
--- a/tests/dhrystone.sh
+++ b/tests/dhrystone.sh
@@ -8,7 +8,7 @@ N_RUNS=10
 function run_dhrystone()
 {
     # Run Dhrystone and extract the DMIPS value
-    output=$($RUN $O/dhrystone.elf 2>&1)
+    output=$($RUN $O/riscv32/dhrystone 2>&1)
     local exit_code=$?
     [ $exit_code -ne 0 ] && fail
     dmips=$(echo "$output" | grep -oE '[0-9]+' | awk 'NR==5{print}')

However, both dhrystone and coremark took significantly longer, making continuous benchmarking impractical.
@vacantron, can you check?

[jserv]

However, both dhrystone and coremark took significantly longer, making continuous benchmarking impractical.

Elapsed time measured on AMD Ryzen Threadripper 2990WX 32-Core Processor: (single iteration)

• Dhrystone: 4m9.398s
• CoreMark: 2m25.966s